Add defaults for TraceConfig properties
Add defaults for TraceConfig properties

This adds sensible defaults to the TraceConfig properties to
resolve some coverity warnings about uninitialised properties (even
though they're never used). This also allows a TraceConfig to be
safely used when requested from a TraceLog that has never run.

Change-Id: Ied49a2faf6f07c6118c35cce92551318205b681f
Reviewed-on: http://review.couchbase.org/66493
Tested-by: buildbot <80754af91bfb6d1073585b046fe0a474ce868509@couchbase.com>
Reviewed-by: Dave Rigby <a09264da4832c7ff1d3bf1608a19f4b870f93750@couchbase.com>

Chippiewill/phosphor,Chippiewill/phosphor