Removed IPython.config.default from the default search path for ipcluster

When ipcluster searches for config files, it should not look in
IPython.config.default because we ALWAYS move the default config
files to cluster_dir (which is still on the search path).

IPython/kernel/clusterdir.py

@@ -401,11 +401,11 b' class ApplicationWithClusterDir(Application):'
             self.log.critical("No config filename found")
 
     def find_config_file_paths(self):
-        # Include our own config directory last, so that users can still find
-        # our shipped copies of builtin config files even if they don't have
-        # them in their ipython cluster directory.
+        # Set the search path to to the cluster directory. We should NOT
+        # include IPython.config.default here as the default config files
+        # are ALWAYS automatically moved to the cluster directory.
         conf_dir = os.path.join(get_ipython_package_dir(), 'config', 'default')
-        self.config_file_paths = (self.cluster_dir, conf_dir)
+        self.config_file_paths = (self.cluster_dir,)
 
     def pre_construct(self):
         # The log and security dirs were set earlier, but here we put them