Partial sync of jsonutils from openstack-common

This makes horizon work with recent versions of anyjson. Note that
there's another jsonutils change in openstack-common, but it requires
timeutils (which adds a dependency on the iso8601 module), so I skipped
it for now.

Changes from openstack-common:

    commit 4c9d439ef24f5afdd74aa9153aa8fc772051e6cb
    Author: Tim Daly Jr <timjr@yahoo-inc.com>
    Date:   Tue Jun 26 02:48:42 2012 +0000

        Add 'filedecoder' method to the jsonutils wrapper module.

        Fixes bug #1017765

        After version 3.3.2, the anyjson library will throw a KeyError if
        filedecoder isn't present.  The filedecoder is just like the decoder
        except it takes a file instead of a string, like json.load() instead
        of json.loads().

        Change-Id: I7bd012a7b4afa9b1ec987c3e6393cc922b5dadff

Change-Id: I912116d56e4e31ae93042929775c8d03dc4fa59e

horizon/openstack/common/jsonutils.py

@@ -130,11 +130,15 @@ def loads(s):
     return json.loads(s)
 
 
+def load(s):
+    return json.load(s)
+
+
 try:
     import anyjson
 except ImportError:
     pass
 else:
     anyjson._modules.append((__name__, 'dumps', TypeError,
-                                       'loads', ValueError))
+                                       'loads', ValueError, 'load'))
     anyjson.force_implementation(__name__)