inotify: fix traceback when the server has been already started

hgext/inotify/__init__.py

@@ -24,7 +24,10 b' def serve(ui, repo, **opts):'
 
     class service:
         def init(self):
-            self.master = server.Master(ui, repo, timeout)
+            try:
+                self.master = server.Master(ui, repo, timeout)
+            except server.AlreadyStartedException, inst:
+                raise util.Abort(str(inst))
 
         def run(self):
             try: