Update the LOG_ macros to not call the logger function when not enabled
Update the LOG_ macros to not call the logger function when not enabled

The problem with calling:

   LOG_DEBUG("Foo {} {} {}", getId(), getBlah(), convert());

Is that all of the methods provided on the LOG_DEBUG line would have
to be called even if the logger would drop the log message.

Tweak the log macros so that we check if the level is enabled
_before_ trying to call the method.

Change-Id: I7a67e54ff3189bfad4d0ea8ee25a7b0dd06bf64c
Reviewed-on: http://review.couchbase.org/89171
Reviewed-by: Tim Bradgate <f1a26ee65f021cb7d82b83dfb09abf144d3eb64f@couchbase.com>
Tested-by: Build Bot <80754af91bfb6d1073585b046fe0a474ce868509@couchbase.com>

daverigby/kv_engine,daverigby/kv_engine,daverigby/kv_engine,daverigby/kv_engine