Sync with Oslo

This will help with porting to Python 3. List of merged commits:

04a1abe59ac39890f57d2eed57d3d1b12bb5d757
12bcdb71ffbe9ee1688beed1f0ddb0c198822682
2cfc1a78d8063cf20083cf7df796d730a576551c
302c7c80b503b8090e8118e45061e8903b5339a9
35dc1d797209f0b22ff3ed3b8a6059961563daee
3b248dd683d83fd564f740ea58565d1bc0bd6cc0
4246ce0f373aa8f8955a99a3b6288a32547d8e80
6650435004af149284f0badb2bb8c89005cc7dab
6d55e26aa379fd043c66d1b7c5bf59a1b4a54632
71c22e9b2fbf04fc91a7343d3de0e0c7f10e3988
84d461e859e4b1eb1a00b9b141df61c37da84d2d
8575d87af49ea276341908f83c8c51db13afca44
885828af2297b20a3f9f8e8f6647f7291f784743
8b2b0b743e84ceed7841cf470afed6a5da8e1d07
9f1e7eb4112067423f845bd99ec52256db1c8bb1
bd5dad97585208ea5e86d636f3dc3b669e361a41
be81d6ba70152e5cdd7e8e9d789b9733c6ff527f
bec3a5eb8157c0c552c6392ccf0da342ffb8da26
c178e567cb48d3bc67dcf06bcbb4c6a97df9f434

Closes-Bug: 1289690
Change-Id: I39fa5e3fa46ffe9448b381ed54759cb4270cc898

glanceclient/openstack/common/importutils.py

@@ -1,5 +1,3 @@
-# vim: tabstop=4 shiftwidth=4 softtabstop=4
-
 # Copyright 2011 OpenStack Foundation.
 # All Rights Reserved.
 #
@@ -60,6 +58,13 @@ def import_module(import_str):
     return sys.modules[import_str]
 
 
+def import_versioned_module(version, submodule=None):
+    module = 'glanceclient.v%s' % version
+    if submodule:
+        module = '.'.join((module, submodule))
+    return import_module(module)
+
+
 def try_import(import_str, default=None):
     """Try to import a module and if it fails return default."""
     try: