phabricator: handle local:commits time being string or int

Authored by Kwan.


phabricator: handle local:commits time being string or int

When setting local:commits arcanist has different behaviour depending on
whether the repo is git or hg. With hg it sets the time as a number, since it
calls PHP's strtotime on the value, but with git it sets it as a string.
Normally this wouldn't be an issue since phabread wouldn't be interacting with
Phabricator Revisions for git repos, but Mozilla has a secondary workflow for
git users that uses the git-cinnabar tool to interact with their hg repos. When
a git-cinnabar user uses the moz-phab tool to submit patches for mozilla-central
it makes use of Mozilla's fork of arcanist, which works with their local git
version of m-c, and thus sets the local:commit time as a string, and then
translates the commit hashes.

Currently when encountering such DREVS phabread dies with "TypeError: %d format:
a number is required, not str".

phabsend also used to set it as a string but wouldn't have encountered the
issue with its own DREVs since it would read hg:meta first.

Differential Revision: https://phab.mercurial-scm.org/D6650