Moves find config to utils because it is useful

This is to prepare for a future patch will will use find
config to load other config files.

Change-Id: Ic9bd9027baf518734c3f51f516651b80d1e752f2

nova/utils.py

@@ -77,6 +77,29 @@ def import_object(import_str):
         return cls()
 
 
+def find_config(config_path):
+    """Find a configuration file using the given hint.
+
+    :param config_path: Full or relative path to the config.
+    :returns: Full path of the config, if it exists.
+    :raises: `nova.exception.ConfigNotFound`
+
+    """
+    possible_locations = [
+        config_path,
+        os.path.join(FLAGS.state_path, "etc", "nova", config_path),
+        os.path.join(FLAGS.state_path, "etc", config_path),
+        os.path.join(FLAGS.state_path, config_path),
+        "/etc/nova/%s" % config_path,
+    ]
+
+    for path in possible_locations:
+        if os.path.exists(path):
+            return os.path.abspath(path)
+
+    raise exception.ConfigNotFound(path=os.path.abspath(config_path))
+
+
 def vpn_ping(address, port, timeout=0.05, session_id=None):
     """Sends a vpn negotiation packet and returns the server session.