Fix error message on "publish" exception in JcontrollerAdmin

In case of ANY exception during "publish" the same error message was being displayed. The JLIB_DATABASE_ERROR_ANCESTOR_NODES_LOWER_STATE message is also irrelevant most of the times, like in non-nested tables.
Changed to show actual message string from the Exception object in catch argument.

To reproduce this error just do anything that will cause exception during publish of an item; then try to change publish state of that item.