Enable H304 check

Enable H304: no relative imports

Fix import in tools/install_venv.py

Change-Id: I099ed65db9b42223eaa4b66a3a5c6113d1cc56fe
Configuration doc for VMware storage backend

The documentation in configuring.rst needs to be populated
for the VMware datastore storage backend.

docImpact

Change-Id: I2064292867e12e699ca0a8ebba6c11f9de3591a5
Closes-Bug: #1275040
Sync latest network_utils module from Oslo

Syncs the latest network_utils from Oslo to help simplify the fix
needed for bug #1216247. Also adds network_utils to
openstack-common.conf.

This also includes the following commits to network_utils:

897aa7c urlsplit issues with IPv6 addresses in python26
35dc1d7 py3kcompat: remove
12bcdb7 Remove vim header
4c22556 Use py3kcompat urlutils functions instead of urlparse
0bf03b7 Add network_utils.urlsplit
e456727 Remove useless logging in networks_utils
7119e29 Enable hacking H404 test.

Change-Id: I63325c9b677c2192d24e7eb73adac272bffd4e0b
Merge "Sync latest network_utils module from Oslo"
Merge "Enable H304 check"
Merge "Configuration doc for VMware storage backend"