R1:17d801a50e94

GitFetch daemon: more verbose

Summary: A smidgen more messaging about what's going on.

Test Plan:
Ran it, saw this:

2012-03-07 5:37:30 PM [STDO] >>> [0] <exec> $ /data/phabricator/bin/list_db_services --tier_name 'cdb.phabricator'
<<< [0] <exec> 47,101 us
...
>>> [9] <exec> $ mkdir -p '/var/repo'
<<< [9] <exec> 41,374 us
Creating new directory /var/repo/fbcode for repo FBCode
>>> [10] <exec> $ git clone --origin origin 'ssh://fbcode.git.vip.facebook.com/data/gitrepos/fbcode.git'…