Remove cityhash.gyp

Remove cityhash.gyp

According to https://code.google.com/p/skia/issues/detail?id=1286 it should be fine to remove this empty gyp file now.

BUG=None
TEST=None
R=epoger@google.com

Committed: http://code.google.com/p/skia/source/detail?r=12481

[epoger, 2013-12-04 15:10:00]

LGTM

let's try it :-)

[commit-bot: I haz the power, 2013-12-04 16:22:21]

CQ is trying da patch. Follow status at
https://skia-tree-status.appspot.com/cq/tfarina@chromium.org/102603004/1

[commit-bot: I haz the power, 2013-12-04 16:30:05]

Change committed as 12481