Ensure route table thread logging can be disabled

The messages written by the route table collector thread are
not affected by the verbose level that the user application
can set. This change allows the complete squelching of the
messages from this thread when all messages are turned off.

Signed-off-by: E. Scott Daniels <daniels@research.att.com>
Change-Id: Iddea13591f28a96f0cfc4630924a9fc11fadd809