Summary:
When we don't provide a repo name, scm_telem_log will run `hg config` to try
and get the path, and fall back to using the basename of the repo directory.
However, this is a bit undesirable, because if we ran this code we already
checked the path, so the repo URL isn't going to magically materialize once `hg
config` asks for it, which means we make a completely redundant call to hg from
scm_telem_log.
By just doing this in logginghelper, we avoid this extra roundtrip.
Reviewed By: StanislavGlebik
Differential Revision: D21572027
fbshipit-source-id: 58e5ab2e3e525edef1ecde039cd968eab8d89172
