data/libvirt: Drop local.hostnames
data/libvirt: Drop local.hostnames

We used to assign both {name}-api and {name}-tnc to the bootstrap and
master nodes.  But we dropped {name}-tnc in 239373f9 (aws/ELBs: merge
tnc with api_internal and cleanup, 2018-09-19, #242).  Now that it's
just the one entry, the local.hostnames indirection is unecessary
complication.

derekhiggins/installer,derekhiggins/installer