Updated openstack/openstack
Project: openstack-dev/devstack  2bb05fdb84aa472299efc714b7c1114a25a3ada2

Promote libffi-dev as a general dependency

libffi-dev/libffi-devel can be requested for rebuilding the
python clients which is an un-skipable part of the devstack install.

Promoting the libffi-devel to a general dependency.

Change-Id: I1dac7fd536b94de1e49aaf335ac29ffae1bd39d1