Summary:
Previously we were not logging sqllock wait times for waits that timed out. This
adds that, and adds a variable to indicate if the lock succeed or failed.
Test Plan: Added a test for the ui.log metrics
Reviewers: #mercurial, quark
Reviewed By: quark
Subscribers: quark
Differential Revision: https://phabricator.intern.facebook.com/D4295786
Signature: t1:4295786:1481154111:442b55f230b53add4e0966223af165f5195ba8b4
