Rebase to an upstream snapshot
    
     - src: rsyslog-7.3.15-20130604git6e72fa6.tar.gz
     - drop patches 3, 4 - merged upstream
     - add a patch to silence warnings emitted by the imuxsock module
     - drop the imkmsg plugin
     - enable compilation of additional modules
       imjournal, mmanon, omjournal, omrabbitmq
     - new subpackages: crypto, rabbitmq
     - add python-docutils and autoconf to global BuildRequires
     - drop the option for backwards compatibility from the
       sysconfig file - it is no longer supported
     - call autoreconf to prepare the snapshot for building