Updated openstack/openstack
Project: openstack/requirements  87674ae3247d894970de1aff407bb1d903b181e0
null
Added argcomplete requirement

This library will be used in python clients to provide command line
completition

Minimum version is 0.6.8 cause it's the first version that works with
PBR generated scripts

Change-Id: Ia2aaa4cd40ebfa29f1c2135a5c99e67484af6de7