revert part of Tons commit r33884.

- rather then use unlink="None", just don't pass unlink as a keyword. This is more pythonic.
- added an RNA flag for properties which cant be unlinked by setting to None.

release/scripts/ui/properties_data_armature.py

@@ -43,9 +43,9 @@ class DATA_PT_context_arm(ArmatureButtonsPanel, bpy.types.Panel):
         space = context.space_data
 
         if ob:
-            layout.template_ID(ob, "data", unlink="None")
+            layout.template_ID(ob, "data")
         elif arm:
-            layout.template_ID(space, "pin_id", unlink="None")
+            layout.template_ID(space, "pin_id")
 
 
 class DATA_PT_skeleton(ArmatureButtonsPanel, bpy.types.Panel):

release/scripts/ui/properties_data_curve.py

@@ -60,9 +60,9 @@ class DATA_PT_context_curve(CurveButtonsPanel, bpy.types.Panel):
         space = context.space_data
 
         if ob:
-            layout.template_ID(ob, "data", unlink="None")
+            layout.template_ID(ob, "data")
         elif curve:
-            layout.template_ID(space, "pin_id", unlink="None") # XXX: broken
+            layout.template_ID(space, "pin_id") # XXX: broken
 
 
 class DATA_PT_shape_curve(CurveButtonsPanel, bpy.types.Panel):

release/scripts/ui/properties_data_mesh.py

@@ -71,9 +71,9 @@ class DATA_PT_context_mesh(MeshButtonsPanel, bpy.types.Panel):
         space = context.space_data
 
         if ob:
-            layout.template_ID(ob, "data", unlink="None")
+            layout.template_ID(ob, "data")
         elif mesh:
-            layout.template_ID(space, "pin_id", unlink="None")
+            layout.template_ID(space, "pin_id")
 
 
 class DATA_PT_normals(MeshButtonsPanel, bpy.types.Panel):

release/scripts/ui/properties_data_metaball.py

@@ -43,9 +43,9 @@ class DATA_PT_context_metaball(DataButtonsPanel, bpy.types.Panel):
         space = context.space_data
 
         if ob:
-            layout.template_ID(ob, "data", unlink="None")
+            layout.template_ID(ob, "data")
         elif mball:
-            layout.template_ID(space, "pin_id", unlink="None")
+            layout.template_ID(space, "pin_id")
 
 
 class DATA_PT_metaball(DataButtonsPanel, bpy.types.Panel):

release/scripts/ui/properties_object.py

@@ -37,7 +37,7 @@ class OBJECT_PT_context_object(ObjectButtonsPanel, bpy.types.Panel):
         ob = context.object
 
         if space.use_pin_id:
-            layout.template_ID(space, "pin_id", unlink="None")
+            layout.template_ID(space, "pin_id")
         else:
             row = layout.row()
             row.label(text="", icon='OBJECT_DATA')