Remove python-netaddr requirement

Remove python-netaddr as a DevStack (stack.sh) requirement,
this does not change any individual project requirements.

Specifically it replaces address_in_net() and adds cidr2netmask()
and maskip() functions.

Change-Id: Ic604437fde2e057faced40a310ab282f3eb27726
Merge "Remove python-netaddr requirement"
Merge remote-tracking branch 'm_src_repo/citrix-fixes' into build-temp