Fix unicode issue

In Python 3, all string is unicode.
Replace unicode() with six.u()
Make use of strutils.to_slug() for slugify() definition

Partial implements: blueprint py33-support

Change-Id: I6a1e19c095a2fbafcbe47b34c7af17e1b0353b9e
Import exceptions module from openstack-common

Partial implements: blueprint py33-support

Change-Id: I5ee3e85e1adf76779831beeb0a91591d342c798d
Import urlutils module from openstack-common

urlutils defines a series of urllib/urlparse modules for Python 2&3
compatability.

Partial implements: blueprint py33-support

Change-Id: I55c2c5d479d2f7a86d3a0c207dc40794006d951c
Replace urllib.quote with urlutils.quote

quote is defined in urlutils for Python2&3 compatability.

Partial implements: blueprint py33-support

Change-Id: I81e667c76544b6bafd81d51d788158f6a062a90c
Merge "Fix unicode issue"
Merge "Import exceptions module from openstack-common"
Merge "Import urlutils module from openstack-common"
Merge "Replace urllib.quote with urlutils.quote"