Avoid creating qpid connection twice in initialization

In current logic, class impl_qpid.Connnection constructor calls
method connection_create twice indirectly. Let us avoid this.

Change-Id: I7618cf3506d857579dc37b338690d05179ba272d
Replace data structures' attribute with six module

In Python 3, some data structures' attribute is different in Python 2.
See http://pythonhosted.org/six/#object-model-compatibility
This is change mapping:

   six               Python 2           Python 3
six.next(it)         it.next()          next(it)
six.iterkeys(dict)   dict.iterkeys()    dict.keys()
six.itervalues(dict) dict.itervalues()  dict.values()

Implements: blueprint make-python3-compatible
Change-Id: Ida48f39ff230860feee7305b93b134c625a21663
Unify different names between Python2 and Python3

Some modules have different names in Python2 and Python3. This patch
make them compatible with Python 3.

 * Use six.moves.filter instead of itertools.ifilter() in Python 2.
 * Use common.py3kcompat.urlutils instead of urllib and urlparse.

Change-Id: Ia27ebf6057d91d0e129fbe90f995cfdaa89efa8a
Merge "Replace data structures' attribute with six module"
Merge "Unify different names between Python2 and Python3"
Merge "Avoid creating qpid connection twice in initialization"