PROTON-455: Added rewrite method to Ruby Messenger class.

git-svn-id: https://svn.apache.org/repos/asf/qpid/proton/trunk@1543565 13f79535-47bb-0310-9956-ffa450edef68
PROTON-456: Added password property to Ruby Messenger class.

git-svn-id: https://svn.apache.org/repos/asf/qpid/proton/trunk@1543595 13f79535-47bb-0310-9956-ffa450edef68