Fix for compositor bug introduced in pynodes branch by removing the default MuteNode for unspecified nodes in the COM_Converter. Not sure why i removed this in the first place, but it means that reroute nodes are not properly replaced in composites. It worked for preview and viewer composite because the reroute nodes are replaced there already by the node tree localization ... this needs to be cleaned up.

git-svn-id: https://svn.blender.org/svnroot/bf-blender/trunk/blender@55437 954f8c5b-7b00-dc11-b283-0030488c597c