apply_issue: 89 ret code on network/Rietveld failures.
apply_issue: 89 ret code on network/Rietveld failures.

This would allow bot_update to differentiate between patch download and
aplication failures.

R=phajdan.jr@chromium.org,sergiyb@chromium.org
BUG=537417

Review URL: https://codereview.chromium.org/1380093003

git-svn-id: fd409f4bdeea2bb50a5d34bb4d4bfc2046a5a3dd@296983 0039d316-1c4b-4281-b951-d872f2087c98

Midrya/chromium,CoherentLabs/depot_tools,disigma/depot_tools,Midrya/chromium,azureplus/chromium_depot_tools,aleonliao/depot_tools,aleonliao/depot_tools,hsharsha/depot_tools,primiano/depot_tools,disigma/depot_tools,Midrya/chromium,CoherentLabs/depot_tools,primiano/depot_tools,duanwujie/depot_tools,aleonliao/depot_tools,primiano/depot_tools,hsharsha/depot_tools,duongbaoduy/gtools,azureplus/chromium_depot_tools,duongbaoduy/gtools,duanwujie/depot_tools,duongbaoduy/gtools,disigma/depot_tools,azureplus/chromium_depot_tools,hsharsha/depot_tools,duanwujie/depot_tools