Revert the path detection

Pylibjuju really needs to better handle path detection and tbh it
shouldn't be reading your home directory and everything should be passed
in.

Author: SimonRichardson

juju/client/jujudata.py

@@ -121,8 +121,7 @@ class FileJujuData(JujuData):
     '''Provide access to the Juju client configuration files.
     Any configuration file is read once and then cached.'''
     def __init__(self):
-        default_data_dir = pathlib.Path(pathlib.Path.home(), ".local", "share", "juju")
-        self.path = os.environ.get('JUJU_DATA', default_data_dir)
+        self.path = os.environ.get('JUJU_DATA') or '~/.local/share/juju'
         self.path = os.path.abspath(os.path.expanduser(self.path))
         # _loaded keeps track of the loaded YAML from
         # the Juju data files so we don't need to load the same