avocado.utils: Add path submodule

Add a module for path related operations in avocado.utils.
Signed-off-by: NLucas Meneghel Rodrigues <lmr@redhat.com>

avocado/utils/path.py

+# This program is free software; you can redistribute it and/or modify
+# it under the terms of the GNU General Public License as published by
+# the Free Software Foundation; either version 2 of the License, or
+# (at your option) any later version.
+#
+# This program is distributed in the hope that it will be useful,
+# but WITHOUT ANY WARRANTY; without even the implied warranty of
+# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.
+#
+# See LICENSE for more details.
+#
+# Copyright: Red Hat Inc. 2013-2014
+# Author: Yiqiao Pu <ypu@redhat.com>
+
+"""
+Avocado path related functions.
+"""
+
+import os
+
+
+def init_dir(*args):
+    """
+    Wrapper around os.path.join that creates dirs based on the final path.
+
+    :param args: List of dir arguments that will be os.path.joined.
+    :type directory: list
+    :return: directory.
+    :rtype: str
+    """
+    directory = os.path.join(*args)
+    if not os.path.isdir(directory):
+        os.makedirs(directory)
+    return directory