Fix T62162: Bones set to unselectable can be fully selected through the viewport in edit mode.

Bone selectability in edit mode now matches the behavior of pose mode
(can no longer be selected).

Reviewed By: Brecht

Differential Revision: http://developer.blender.org/D4469

source/blender/editors/armature/armature_select.c

@@ -631,6 +631,10 @@ bool ED_armature_edit_select_pick(bContext *C, const int mval[2], bool extend, b
 		ED_view3d_viewcontext_init_object(&vc, basact->object);
 		bArmature *arm = vc.obedit->data;
 
+		if (!EBONE_SELECTABLE(arm, nearBone)) {
+			return false;
+		}
+
 		if (!extend && !deselect && !toggle) {
 			uint objects_len = 0;
 			Object **objects = BKE_view_layer_array_from_objects_in_edit_mode_unique_data(vc.view_layer, vc.v3d, &objects_len);