Revert "Whitelist external netaddr requirement"
Revert "Whitelist external netaddr requirement"

This reverts commit 01dc81aa148adaa127281f197047636cf2d2c898.

The netaddr package is now hosted on PyPI, so this workaround is
not needed anymore.

Change-Id: I76957aa5e276036921696f27e18efb5494b33120
Closes-Bug: #1266513

metacloud/python-keystoneclient,magic0704/python-keystoneclient,darren-wang/ksc,magic0704/python-keystoneclient,ging/python-keystoneclient,alexpilotti/python-keystoneclient,sdpp/python-keystoneclient,Mercador/python-keystoneclient,ging/python-keystoneclient,alexpilotti/python-keystoneclient,jamielennox/python-keystoneclient,metacloud/python-keystoneclient,klmitch/python-keystoneclient,sdpp/python-keystoneclient,Mercador/python-keystoneclient,jamielennox/python-keystoneclient,klmitch/python-keystoneclient,darren-wang/ksc,jamielennox/python-keystoneclient