Fixing MultiEngineClient.activate to use new plugin system.

IPython/kernel/multiengineclient.py

@@ -272,7 +272,7 b' class InteractiveMultiEngineClient(object):'
         except NameError:
             print "The IPython parallel magics (%result, %px, %autopx) only work within IPython."
         else:
-            pmagic = ip.get_component('parallel_magic')
+            pmagic = ip.plugin_manager.get_plugin('parallel_magic')
             if pmagic is not None:
                 pmagic.active_multiengine_client = self
             else: