Prefer IPYTHONDIR over IPYTHON_DIR.

IPython/core/application.py

@@ -186,7 +186,7 b' class BaseIPythonApplication(Application):'
         if not os.path.exists(readme):
             path = os.path.join(get_ipython_package_dir(), u'config', u'profile')
             shutil.copy(os.path.join(path, 'README'), readme)
-        self.log.debug("IPYTHON_DIR set to: %s" % new)
+        self.log.debug("IPYTHONDIR set to: %s" % new)
 
     def load_config_file(self, suppress_errors=True):
         """Load the config file.

IPython/utils/path.py

@@ -260,7 +260,7 b' def get_ipython_dir():'
     xdg_dir = get_xdg_dir()
     
     # import pdb; pdb.set_trace()  # dbg
-    ipdir = env.get('IPYTHON_DIR', env.get('IPYTHONDIR', None))
+    ipdir = env.get('IPYTHONDIR', env.get('IPYTHON_DIR', None))
     if ipdir is None:
         # not set explicitly, use XDG_CONFIG_HOME or HOME
         home_ipdir = pjoin(home_dir, ipdir_def)