JERSEY-2006: LoggingFilter does not respect order of headers.

 Issue is only with HttpUrlConnector, especially with HttpURLConnection
 which returns map of headers in HashMap rather than in some sort
 "key-sorted" map. Updated LoggingFilter to sort headers before they're
 printed out.

Change-Id: Ie37a71dbd93384b3bc75be0af8e45e72839bc255