Another random failure in LocaleImportFunctionalTest

[indigoxela]

Part of #1478

This is a follow-up to #2611, where a part of LocaleImportFunctionalTest got fixed.

It seems like we need another one - different line, different task.

Detailed test results
---------------------
Fail      Other      locale.test        895 LocaleImportFunctionalTest->testAut


---- Locale: Translation import (LocaleImportFunctionalTest) ----


Status    Group      Filename          Line Function                            
--------------------------------------------------------------------------------
    Language file automatically imported.

The previous one fixed file_prepare_directory() in function setUp().

The above failure probably isn't new, but it's not covered by the previous fix. Now we're dealing with something in testAutomaticModuleTranslationImportLanguageEnable().

Potentially $this->randomName(16); is a little too random? Needs more investigation.