Bug 1128141 - HostController gets DOWN when name attribute in host.xml is
empty

I discovered we don't have to read HC/DC's name from host.xml at all, since
this value is provided by API via 'local-host-name' attribute. So I rewrote
BaseServerComponent#findASHostName() to use API which fixes this issue.
ServerControl class was also affected by this change - it required
xmlInputFactory (before used for reading host.xml content) which became
useless and was removed.

(cherry picked from commit ef11bc292e57e5133e5c1aee95947fcbd0f662e6)
Signed-off-by: Thomas Segismont <tsegismo@redhat.com>