Prettier wfLogProfilingData() log message

Make the profiler logging output introduced in Iae11e1e a little nicer.
Stop adding the Profiler::getRawData() information and add the URL and
textual report to the default log message. When testing with a Monolog
logger and Logstash the getRawData output from the Xhprof profiler was
found to be too big to be usable. The default message output was found
to be less informative than desirable when a PSR-3 logger other than
MWLoggerLegacyLogger was used. MWLoggerLegacyLogger implements special
backwards compatible formatting for the profileoutput channel that will
not be effected by this change.

Change-Id: Id326aed4f72a3489fac30661c101ac3bb3af2530