Revert "Use the python implementation of instack-install-undercloud"

This reverts commit 79a911a94a.

The python implementation has logging setup in the wrong
place to be used directly. It is safer to revert this for
now, and add it back when it will not cause us to lose all
output from `openstack undercloud install`.

rdomanager_oscplugin/v1/undercloud.py

@@ -16,9 +16,9 @@
 """Plugin action implementation"""
 
 import logging
+import subprocess
 
 from cliff import command
-from instack_undercloud import undercloud
 
 
 class InstallPlugin(command.Command):
@@ -30,7 +30,6 @@ class InstallPlugin(command.Command):
     def take_action(self, parsed_args):
         self.log.debug("take_action(%s)" % parsed_args)
 
-        # TODO(trown): Make the location of the instack root dir configurable
-        undercloud.install('.')
+        subprocess.check_call("instack-install-undercloud")
 
         return