remove the over zealous warning. This is actually okay

modules/Bio/EnsEMBL/DBSQL/AssemblyMapperAdaptor.pm

@@ -222,11 +222,15 @@ sub fetch_by_CoordSystems {
   my @mapping_path = @{$csa->get_mapping_path($cs1,$cs2)};
 
   if(!@mapping_path) {
-    warning(
-      "There is no mapping defined between these coord systems:\n" .
-      $cs1->name() . " " . $cs1->version() . " and " . $cs2->name() . " " .
-      $cs2->version()
-    );
+
+    # It is perfectly fine not to have a mapping. No warning needed really
+    # Just check the return code!!
+
+#    warning(
+#      "There is no mapping defined between these coord systems:\n" .
+#      $cs1->name() . " " . $cs1->version() . " and " . $cs2->name() . " " .
+#      $cs2->version()
+#    );
     return undef;
   }