Fix for #35253, Cannot animate X, Y, Z values in nodes with vector sub-menu. The "component menu" template used for these socket buttons opens a popup, but this ui function does not support RNA info directly. Setting the uiBut rna pointer directly solves it.

git-svn-id: https://svn.blender.org/svnroot/bf-blender/trunk/blender@56581 954f8c5b-7b00-dc11-b283-0030488c597c