Fix for own mistake in r57252, needs to unset id.lib of the newly copied tree instead of the old one.

git-svn-id: https://svn.blender.org/svnroot/bf-blender/trunk/blender@57255 954f8c5b-7b00-dc11-b283-0030488c597c
Removed the "Make Local?" popup from group node edit operator on linked node groups. This is no longer necessary since we can now quite safely display linked node trees in general (this check was already
meaningless for material node trees and the like as demonstrated by bug #35640, so rather pointless).

git-svn-id: https://svn.blender.org/svnroot/bf-blender/trunk/blender@57256 954f8c5b-7b00-dc11-b283-0030488c597c