Add python-alembic
Add python-alembic

neutron now requires a newer version of this than what is in rdo/kilo,
add it explicitly to rdoinfo until we are requiring rdo/liberty.

hguemar/rdoinfo,trown/rdoinfo,xbezdick/rdoinfo,eggmaster/rdoinfo,redhat-openstack/rdoinfo,javierpena/rdoinfo