Fix gyp when GYP_GENERATORS is set
Fix gyp when GYP_GENERATORS is set

(Submitted for piman) for review 164367.

BUG=None
TEST=None
TBR=piman


Review URL: http://codereview.chromium.org/165388

csulmone/gyp,csulmone/gyp,csulmone/gyp,csulmone/gyp