Interim commit to add a VERBOSE variable to fwknopd.
Fixed use of --verbose command line switch.

Set default log verbosity to LOG_INFO in the log_msg driver.
s/VERBOSITY/VERBOSE/g on the server side for consistency purposes.
* Mentionned the VERBOSE variable in fwknopd.conf.
* Made sure the -v command line switch overrides the value of the
  VERBOSE variable set in an fwknopd.conf file.
Merge remote-tracking branch 'upstream/master'
Merge remote-tracking branch 'fjoncourt/master'