mon: fix init sequence when not daemonizing

We made the common_init_finish and chdir conditional on daemonize in commit
2e0dd5ae6c8751e33d456b2b06c1204b63db959a, breaking init (asok at least)
when -f is specified (as with upstart).

Signed-off-by: Sage Weil <sage@inktank.com>
Reviewed-by: Greg Farnum <greg@inktank.com>