MULE-7789: Update mule-transports-http to tomcat 6+

mule-transports-http depends on tomcat 5.5.23 for cookie processing.
Upgraded to tomcat 6 version used by mule elsewhere using
${tomcatVersion}.  Tomcat moved this into coyote.  Verified working in
tomcat 6+.  Defaulted httpOnly to false in this instance since it was
not part of tomcat 5 and not part of cookie from commons-httpclient and
thus was naturally already false.  In tomcat 6, httpOnly is configurable
and default in tomcat 7+.  This seemed most appropriate way to get onto
tomcat 6+ as tomcat 5 is end of life and solved use case we had running
mule within tomcat 7 & 8.