Fix not existing function name in booth-site OCF Script

There was a function call named controld_monitor which
was not found in booth-site OCF Script. Perhaps a copy
and paste mistake from the controld Script. Replaced it
with the right function booth_monitor.

Fixes issues like this:

OCF_ROOT=/usr/lib/ocf OCF_RESKEY_daemon=booth \
/usr/lib/ocf/resource.d/pacemaker/booth-site start
booth: no process found
/usr/lib/ocf/resource.d/pacemaker/booth-site: line 107:
controld_monitor: command not found

Signed-off-by: Joerg Frede <frede@b1-systems.de>