Don't fetch tags etc. when there's a lock and you do "start"

[avar]

$ git-deploy start
# INFO : git fetch --tags origin
# INFO : (not updating working directory)
# INFO : git fetch origin
# INFO : (not updating working directory)
# INFO : From git.booking.com:/gitroot/main
# INFO :    0d9028e..65a8054  trunk      -> origin/trunk
# INFO : Starting step 'start' at 2012-02-02 16-22-01
# FATAL: You may not start a new rollout as it looks like one is already in progress!
# FATAL: Failed to create lock dir '.git/deploy' because 'File exists'
# FATAL: Log:
# FATAL:        start:  2012-02-02 16:19:28     trunk   110bc23d8204dae87b2af259a02d47cd08711589        717     slanning