Fix depset issues with/upgrade to Bazel 0.27.1

[danfabi]

This PR updates rules_closures and Bazel.

depset is no longer iterable starting from Bazel 0.27.0.

[Yannic]

Thanks! Having rules break because of --incompatible_* changes is always a bit annoying.

LGTM w/ nit

[danfabi]

Done!

[nghialv]

Thank you. Can we have a merge of this soon?

[stanley-cheung]

Apparently, when executing ./bazel-0.27.0-installer-linux-x86_64.sh --user,

this is the error message:

## Build information
   - [Commit](https://github.com/bazelbuild/bazel/commit/c82eb48)
Uncompressing....../home/kbuilder/bin/bazel: relocation error: /home/kbuilder/bin/bazel: symbol _ZTVNSt7__cxx1115basic_stringbufIcSt11char_traitsIcESaIcEEE, version GLIBCXX_3.4.21 not defined in file libstdc++.so.6 with link time reference


[ID: 5297890] Build finished after 815 secs, exit value: 127

Could be an environment issue.

[Yannic]

Is Kokoro using Ubuntu 14.04? Bazel started building its releases on 16.04 starting with 0.27.0 which could cause issues like that.
https://blog.bazel.build/2019/06/17/bazel-0.27.0.html

[danfabi]

Yep, sounds like Ubuntu 14.04 is the issue. Is there anything I can do?

[Globegitter]

There was some discussion here: bazelbuild/bazel#7816 (comment) and it seems the next release should support Ubuntu 14.04 again.

[Yannic]

@factuno-db Can we upgrade to / test with Bazel 0.27.1?

[danfabi]

Sure, I've checked daily for new Bazel releases ;-)

[stanley-cheung]

Yay tests passed :)

[stanley-cheung]

Thanks for the update!