Problems with code integrity when skeleton folder is empty

[nicomaha]

Steps to reproduce

1. delete the following files:

- core/skeleton/Documents/About.odt
- core/skeleton/Documents/About.txt
- core/skeleton/Nextcloud Manual.pdf
- core/skeleton/Nextcloud.mp4
- core/skeleton/Photos/Coast.jpg
- core/skeleton/Photos/Hummingbird.jpg
- core/skeleton/Photos/Nut.jpg

1. go to Nextcloud and get the warning about problems with code integrity check at the admin panel

Expected behaviour

No warning because the skeleton files are not really required.

Actual behaviour

Warning although the skeleton files are deleted on purpose.

Server configuration

Operating system:

Web server: 1und1 shared hosting

Database: MySQL

PHP version: 7.0.9

Nextcloud version: 10

Updated from an older Nextcloud/ownCloud or fresh install: update from Nextcloud 9

Where did you install Nextcloud from: downloaded zip file

Signing status:

Signing status

Technical information
=====================
The following list covers which files have failed the integrity check. Please read
the previous linked documentation to learn more about the errors and how to fix
them.

Results
=======
- core
    - FILE_MISSING
        - core/skeleton/Documents/About.odt
        - core/skeleton/Documents/About.txt
        - core/skeleton/Nextcloud Manual.pdf
        - core/skeleton/Nextcloud.mp4
        - core/skeleton/Photos/Coast.jpg
        - core/skeleton/Photos/Hummingbird.jpg
        - core/skeleton/Photos/Nut.jpg

Raw output
==========
Array
(
    [core] => Array
        (
            [FILE_MISSING] => Array
                (
                    [core/skeleton/Documents/About.odt] => Array
                        (
                            [expected] => 1cc2eae96696437edac41a8f9bc04a2ce2e8aac132cee19239222ef0f0ed0722a8279d6dae2073c230f9f2015f03559827a4bdd11ac068d2ee31f8bef9ec8b95
                            [current] => 
                        )

                    [core/skeleton/Documents/About.txt] => Array
                        (
                            [expected] => 246d73856029aac8fb5cfda0644c473bcc519017b8284e0b850b67025562170cf4c1afa39f037cff3c9a331f85ab29266353de184c039907a54a680a54c15040
                            [current] => 
                        )

                    [core/skeleton/Nextcloud Manual.pdf] => Array
                        (
                            [expected] => 7606983fcac0f708c19526acfaefffce6442b601b802664d99f4ebb2e8fdd909ed02e03c9c70fb37ef939134de5df2e8993345626d91f04b2bc1713dac0b787f
                            [current] => 
                        )

                    [core/skeleton/Nextcloud.mp4] => Array
                        (
                            [expected] => 20629a6a9e8750beac07541c77e8e694fb527cc653f2d6626d73c7381070726af4062169010947229e1b904e56308928e4897e31a7809bddd70dd2027ef5471a
                            [current] => 
                        )

                    [core/skeleton/Photos/Coast.jpg] => Array
                        (
                            [expected] => 2bb4fd0ca9fbcb71b3565f1c019233aac9d22d19e25a6c1afe1ba37dbe33a2d282ead22aafd6e5a012bb206c9606f1056d9f83955034a11d2c531d435f097933
                            [current] => 
                        )

                    [core/skeleton/Photos/Hummingbird.jpg] => Array
                        (
                            [expected] => 4c5c440aabadb7bc084502513f34691754ad0cd5b7dc60af5294c5076e17e102d209b2fec4d1a1f38b940887c6f8eb16efa9240944116d17e6c4a36689987d84
                            [current] => 
                        )

                    [core/skeleton/Photos/Nut.jpg] => Array
                        (
                            [expected] => 0a82a718fc89d438c5887bac2b4fe7f32ec39a3cf9aab38e7f544ed8493d328d2247fa4efa85d4caa650550c34f305ba7eb12973d2487e10507cb2ab0f38c122
                            [current] => 
                        )

                )

        )

)

List of activated apps:

App list

Enabled:
  - admin_audit: 1.0.0
  - comments: 1.0.0
  - dav: 1.0.0
  - direct_menu: 0.9.2
  - federatedfilesharing: 1.0.1
  - federation: 1.0.1
  - files: 1.5.2
  - files_pdfviewer: 0.8.1
  - files_sharing: 1.0.0
  - files_texteditor: 2.1
  - files_trashbin: 1.0.0
  - files_versions: 1.3.0
  - files_videoplayer: 0.9.8
  - gallery: 15.0.0
  - notifications: 0.3.0
  - password_policy: 1.0.0
  - provisioning_api: 1.0.0
  - serverinfo: 1.1.1
  - survey_client: 0.1.5
  - systemtags: 1.0.2
  - templateeditor: 0.1
  - theming: 1.0.1
  - updatenotification: 1.0.1
  - workflowengine: 1.0.1
Disabled:
  - activity
  - encryption
  - external
  - files_accesscontrol
  - files_automatedtagging
  - files_external
  - files_retention
  - firstrunwizard
  - user_external
  - user_ldap
  - user_saml

### Client configuration

Browser: Safari 9.1.3

Operating system: OSX 10.11.6

[LukasReschke]

server/config/config.sample.php

Lines 217 to 222 in e89ce4a

	/**
	* The directory where the skeleton files are located. These files will be
	* copied to the data directory of new users. Leave empty to not copy any
	* skeleton files.
	*/
	'skeletondirectory' => '/path/to/nextcloud/core/skeleton',