Fixed issue with try where patchset is passed.
The new try execution should only be triggered when a user just passes the rietveld issue number. Usually, if your branch has a working patchset already defined, it shouldn't think the user passed it. The code has been updated to force patchset to be None (not 0 or any other number) so that specific occurence wont happen again.
TBR=maruel
BUG=None
TEST=git try, git try --issue=123, git try --issue=123 --patchset=0, should all work fine now.
Committed:
http://src.chromium.org/viewvc/chrome?view=rev&revision=35889