fixes spelling of filename.

Window.c was calling undo_push_mesh, even for non mesh objects, exiting editmode would crash for any non mesh object (found with the armature symmetry script), bad juju.

source/blender/python/api2_2x/Window.c

@@ -901,11 +901,11 @@ static PyObject *M_Window_EditMode( PyObject * self, PyObject * args )
 			if( !G.obedit )
 				enter_editmode(0);
 		} else if( G.obedit ) {
-			if( do_undo && U.undosteps != 0 ) {
-				if( undo_str_len > 63 )
-					undo_str[63] = '\0';	/* 64 is max */
-				undo_push_mesh( undo_str );	/* use better solution after 2.34 */
-			}
+			
+			if( undo_str_len > 63 )
+				undo_str[63] = '\0';	/* 64 is max */
+			
+			BIF_undo_push( undo_str ); /* This checks user undo settings */
 			exit_editmode( EM_FREEDATA );
 		}
 	}