Horizon requires that Nova, Neutron(Nova Network), Glance,
and Keystone are running. Therefore, the container needs to
check for the availablity of each service on startup.
The config file is not a .ini file, but rather a python file
so it requires using sed instead of crudini.
Change-Id: I5ed14514881fe9aef688ca08bcb94881ef5b25cb
fdb5c77a90