Support Gerrit snapshot versions
Support Gerrit snapshot versions

These may be named git-snapshot-VERSION.war, where VERSION is the long
format defined in git-describe(1). In particular, this may include a
number of commits after the given tag name; treat more commits since
the tag as a higher version number. This is arguably not always
strictly correct due to non-linear history, but the maintainers expect
the total number of such snapshot versions to be low, and can remove
old snapshot versions that don't sort correctly.

Slightly de-obfuscate some of the variable names and logic while we're
at it.

R=szager@chromium.org
BUG=

Review URL: https://codereview.chromium.org/164023005

git-svn-id: fd409f4bdeea2bb50a5d34bb4d4bfc2046a5a3dd@251888 0039d316-1c4b-4281-b951-d872f2087c98

fanjunwei/depot_tools,fracting/depot_tools,yetu/repotools,azunite/chrome_build,duongbaoduy/gtools,disigma/depot_tools,michalliu/chromium-depot_tools,cybertk/depot_tools,smikes/depot_tools,ajohnson23/depot_tools,smikes/depot_tools,primiano/depot_tools,Chilledheart/depot_tools,Chilledheart/depot_tools,cybertk/depot_tools,withtone/depot_tools,kaiix/depot_tools,withtone/depot_tools,cybertk/depot_tools,Chilledheart/depot_tools,fanjunwei/depot_tools,sarvex/depot-tools,Phonebooth/depot_tools,azureplus/chromium_depot_tools,CoherentLabs/depot_tools,azureplus/chromium_depot_tools,G-P-S/depot_tools,kromain/chromium-tools,SuYiling/chrome_depot_tools,Neozaru/depot_tools,ajohnson23/depot_tools,npe9/depot_tools,kaiix/depot_tools,gcodetogit/depot_tools,Neozaru/depot_tools,eatbyte/depot_tools,G-P-S/depot_tools,Neozaru/depot_tools,smikes/depot_tools,Chilledheart/depot_tools,disigma/depot_tools,hsharsha/depot_tools,liaorubei/depot_tools,yetu/repotools,Phonebooth/depot_tools,duanwujie/depot_tools,xuyuhan/depot_tools,fanjunwei/depot_tools,fracting/depot_tools,disigma/depot_tools,chinmaygarde/depot_tools,sarvex/depot-tools,xuyuhan/depot_tools,xuyuhan/depot_tools,Midrya/chromium,cybertk/depot_tools,cpanelli/-git-clone-https-chromium.googlesource.com-chromium-tools-depot_tools,Neozaru/depot_tools,airtimemedia/depot_tools,fracting/depot_tools,gcodetogit/depot_tools,Midrya/chromium,liaorubei/depot_tools,chinmaygarde/depot_tools,kromain/chromium-tools,primiano/depot_tools,aleonliao/depot_tools,azureplus/chromium_depot_tools,HackFisher/depot_tools,CoherentLabs/depot_tools,smikes/depot_tools,SuYiling/chrome_depot_tools,michalliu/chromium-depot_tools,michalliu/chromium-depot_tools,duongbaoduy/gtools,eatbyte/depot_tools,Chilledheart/depot_tools,michalliu/chromium-depot_tools,mlufei/depot_tools,eatbyte/depot_tools,npe9/depot_tools,withtone/depot_tools,mlufei/depot_tools,sarvex/depot-tools,mlufei/depot_tools,HackFisher/depot_tools,npe9/depot_tools,sarvex/depot-tools,yetu/repotools,liaorubei/depot_tools,SuYiling/chrome_depot_tools,chinmaygarde/depot_tools,cpanelli/-git-clone-https-chromium.googlesource.com-chromium-tools-depot_tools,Neozaru/depot_tools,azunite/chrome_build,kromain/chromium-tools,fanjunwei/depot_tools,aleonliao/depot_tools,liaorubei/depot_tools,airtimemedia/depot_tools,G-P-S/depot_tools,Phonebooth/depot_tools,duanwujie/depot_tools,smikes/depot_tools,G-P-S/depot_tools,airtimemedia/depot_tools,HackFisher/depot_tools,airtimemedia/depot_tools,duongbaoduy/gtools,Midrya/chromium,HackFisher/depot_tools,kaiix/depot_tools,azunite/chrome_build,Phonebooth/depot_tools,ajohnson23/depot_tools,cybertk/depot_tools,cpanelli/-git-clone-https-chromium.googlesource.com-chromium-tools-depot_tools,npe9/depot_tools,kromain/chromium-tools,xuyuhan/depot_tools,hsharsha/depot_tools,aleonliao/depot_tools,duanwujie/depot_tools,hsharsha/depot_tools,primiano/depot_tools,gcodetogit/depot_tools,eatbyte/depot_tools