Use constant time comparison in tempURL

Use constant time comparison when evaluating tempURL to avoid timing
attacks (CVE-2014-0006). This is the havana backport of the master
patch.

Fixes bug 1265665

Change-Id: I11e4ad83cc4077e52adf54a0bd0f9749294b2a48
Set defaultbranch in .gitreview to stable/havana

This allows people run git-review without any arguments and it will push
to the correct branch.

Change-Id: I14f42e5f696ef670ead326ad74a96557ddf3148c
Merge "Set defaultbranch in .gitreview to stable/havana" into stable/havana