Made the tooltip for rigid body constraint "Connect" operator clearer

Previously it wasn't clear what it was supposed to be doing, or what was
required for it to work.
TODO: figure out why the operator redo settings panel won't work. The workflow
here is still a bit clunky.


git-svn-id: https://svn.blender.org/svnroot/bf-blender/trunk/blender@54134 954f8c5b-7b00-dc11-b283-0030488c597c