Fixing two bugs in the handling of paths and profiles.

* If a user is using a profile, but doesn't have the subconfig installed
  we just pass silently. Before, we raised an IOError.
* My new expand_path function had a stupid bug in it.

IPython/config/loader.py

@@ -244,8 +244,14 b' class PyFileConfigLoader(FileConfigLoader):'
         # with the parents.
         def load_subconfig(fname):
             loader = PyFileConfigLoader(fname, self.path)
-            sub_config = loader.load_config()
-            self.config._merge(sub_config)
+            try:
+                sub_config = loader.load_config()
+            except IOError:
+                # Pass silently if the sub config is not there. This happens
+                # when a user us using a profile, but not the default config.
+                pass
+            else:
+                self.config._merge(sub_config)
 
         # Again, this needs to be a closure and should be used in config
         # files to get the config being loaded.

IPython/utils/genutils.py

@@ -1754,11 +1754,11 b' def expand_path(s):'
     # alone an empty var. But, we need the $ to remains there (it indicates
     # a hidden share).
     if os.name=='nt':
-        s.replace('$\\', 'IPYTHON_TEMP')
-    s2 = os.path.expandvars(os.path.expanduser(s))
+        s = s.replace('$\\', 'IPYTHON_TEMP')
+    s = os.path.expandvars(os.path.expanduser(s))
     if os.name=='nt':
-        s2.replace('IPYTHON_TEMP', '$\\')
-    return s2
+        s = s.replace('IPYTHON_TEMP', '$\\')
+    return s
 
 def list_strings(arg):
     """Always return a list of strings, given a string or list of strings