Blender Git Loki

remove "Select Linked" from the particle select and context menu

The operator in its current state is based on mouse position and doesnt
make sense to be called from a menu.
(In fact it should be called 'select_linked_pick' internally and a
separate 'select_linked' should be implemented similar to how "Select
Linked" works for meshes, curves etc -- see D6823 for this)

Differential Revision: https://developer.blender.org/D6822