Livesearch doesn't log data to watchdog

Each live search generates a watchdog entry. The watchdog message is 'Search: %keys (%type).'

The %keys and %type variables are not being properly substituted.

The attached patch fixes the message using the same format/substitutions used by the core Search module: e.g.
Live Search: search term (Content).

The patch also changes the watchdog type to livesearch instead of , so it is clear which module generated the message.