Allow user.name and user.email to drive reflog entry.

Allow user.name and user.email to drive reflog entry.

Apparently calling setup_ident() after git_config causes the
user.name and user.email values read from the config file to be
replaced with the data obtained from the host.  This means that
users who have setup their email address in user.email will instead
be writing reflog entries with their hostname.

Moving setup_ident() to before git_config in update-ref resolves
this ordering problem.

Signed-off-by: Shawn O. Pearce <spearce@spearce.org>
Signed-off-by: Junio C Hamano <junkio@cox.net>