[3074] Add logging

src/bin/bind10/init.py.in

@@ -337,6 +337,7 @@ class Init:
                 self.__propagate_component_config(new_config['components'])
             return isc.config.ccsession.create_answer(0)
         except Exception as e:
+            logger.error(BIND10_RECONFIGURE_ERROR, e)
             return isc.config.ccsession.create_answer(1, str(e))
 
     def get_processes(self):

src/bin/bind10/init_messages.mes

@@ -325,3 +325,7 @@ the configuration manager to start up.  The total length of time Init
 will wait for the configuration manager before reporting an error is
 set with the command line --wait switch, which has a default value of
 ten seconds.
+
+% BIND10_RECONFIGURE_ERROR Error applying new config: %1
+A new configuration was received, but there was an error doing the
+re-configuration.