DevTools: make checker more robust
I discovered that the checker has been not properly checking for the last
~3 months because it was stuck on an old commit hash.
This avoids these types of issues in the future:
* Relies on git fetch instead of git pull so it doesn't have issues such
as file collision
* Sends an email if it hits an error on a git command
I bumped the checking rate from 30 minutes to 3 hours since there's little
benefit to checking more frequently because we're only checking for commits
trailing by 12 hours.
Bug: none
Change-Id: I2fc587155808f38a7b0b4538803e90060188d932
1 file changed
