Move landmines into gyp_chromium

This ensures that the environment that's passed to gyp is the one that
landmines.py uses to determine when to set landmines.

Also, fix '2013e' not being detected as a 2013 switch.

BUG=309197, 323300
R=iannucci@chromium.org

Review URL: https://codereview.chromium.org/153073004

git-svn-id: svn://svn.chromium.org/chrome/trunk/src@249242 0039d316-1c4b-4281-b951-d872f2087c98
Update .DEPS.git

git-svn-id: svn://svn.chromium.org/chrome/trunk/src@249243 0039d316-1c4b-4281-b951-d872f2087c98
SVN changes up to revision 249243