Remove all_android.gyp.

Remove all_android.gyp.

It's been unused for two weeks, and should be a noop for everyone who sourced
envsetup since.

If you see an error message like

  gyp: buid/all_android.gyp not found (cwd: /path/to/chrome/src)

after this change, open a fresh shell (and source envsetup),
or run `unset CHROMIUM_GYP_FILE`.

Also remove the code for unsetting CHROMIUM_GYP_FIE from envsetup
and fold the one line left in common_gyp_vars into its only caller.
BUG=330631
R=torne@chromium.org

Committed: https://src.chromium.org/viewvc/chrome?view=rev&revision=248748

[Nico, 2014-02-04 16:07:01]

(slightly increased this in scope in patch set 3)

[Torne, 2014-02-04 16:24:36]

lgtm

[Nico, 2014-02-04 16:35:01]

The CQ bit was checked by thakis@chromium.org

[commit-bot: I haz the power, 2014-02-04 16:35:59]

CQ is trying da patch. Follow status at
https://chromium-status.appspot.com/cq/thakis@chromium.org/150903005/80001

[commit-bot: I haz the power, 2014-02-04 17:44:25]

The CQ bit was unchecked by commit-bot@chromium.org

[commit-bot: I haz the power, 2014-02-04 17:44:25]

Retried try job too often on win_rel for step(s) base_unittests, browser_tests,
interactive_ui_tests, net_unittests, unit_tests
http://build.chromium.org/p/tryserver.chromium/buildstatus?builder=win_rel&nu...

[Nico, 2014-02-04 17:59:32]

Committed patchset #3 manually as r248748 (presubmit successful).