Tool System: store keymap name in tool instead of the keymap

Resetting keymaps caused them to become invalid (crashing on access).

release/scripts/startup/bl_ui/space_toolsystem_common.py

@@ -306,7 +306,7 @@ class ToolSelectPanelHelper:
         if km is None:
             km = kc.keymaps.new(km_idname, space_type=cls.bl_space_type, region_type='WINDOW', tool=True)
             keymap_fn[0](km)
-        keymap_fn[0] = km
+        keymap_fn[0] = km.name
 
     # Special internal function, gives use items that contain keymaps.
     @staticmethod
@@ -354,9 +354,9 @@ class ToolSelectPanelHelper:
         for context_mode_test, tools in cls.tools_all():
             if context_mode_test == context_mode:
                 for item in cls._tools_flatten_with_keymap(tools):
-                    km = item.keymap[0]
+                    km_name = item.keymap[0]
                     # print((km.name, cls.bl_space_type, 'WINDOW', []))
-                    yield (km.name, cls.bl_space_type, 'WINDOW', [])
+                    yield (km_name, cls.bl_space_type, 'WINDOW', [])
 
     # -------------------------------------------------------------------------
     # Layout Generators
@@ -604,7 +604,7 @@ def _activate_by_item(context, space_type, item, index):
     tool = ToolSelectPanelHelper._tool_active_from_context(context, space_type, create=True)
     tool.setup(
         name=item.text,
-        keymap=item.keymap[0].name if item.keymap is not None else "",
+        keymap=item.keymap[0] if item.keymap is not None else "",
         cursor=item.cursor or 'DEFAULT',
         gizmo_group=item.widget or "",
         data_block=item.data_block or "",