Replace qpid_host with qpid_hostname

This patch replaces `qpid_host` with `qpid_hostname` in both the
qpid manifest and the spec file class. `qpid_host` has been shipped
as the parameter to specify qpid's hostname, although the correct one is
`qpid_hostname`.

Closes-bug 1242715

(cherry picked from commit 8eee78c69d6e29aa1151bf80e69d420bf9fbb838)

Conflicts:
	manifests/notify/qpid.pp

Change-Id: I6fe9f97b60cb155eca8a35ea65f8eac6a6c08f4d