Removed the host FQDN from the exception message

Deletion of an instance after disabling the hypervisor by a non-admin
 user leaks the host fqdn in fault msg of instance.Removing the
'host' field from the error message of HypervisorUnavaiable
cause it's leaking host fqdn to non-admin users. The admin user will
see the Hypervisor unavailable exception msg but will be able to figure
on which compute host the guest is on and that the connection is broken.

Change-Id: I0eae19399670f59c17c9a1a24e1bfcbf1b514e7b
Closes-Bug: #1851587
(cherry picked from commit a89ffab)
(cherry picked from commit ff82601)
(cherry picked from commit c5abbd1)
(cherry picked from commit d5ff9f8)
(cherry picked from commit 8c4af53)

nova/exception.py

@@ -504,7 +504,7 @@ class ComputeResourcesUnavailable(ServiceUnavailable):
 
 
 class HypervisorUnavailable(NovaException):
-    msg_fmt = _("Connection to the hypervisor is broken on host: %(host)s")
+    msg_fmt = _("Connection to the hypervisor is broken on host")
 
 
 class ComputeServiceUnavailable(ServiceUnavailable):

nova/virt/libvirt/host.py

@@ -449,7 +449,7 @@ def get_connection(self):
             rpc.get_notifier('compute').error(nova_context.get_admin_context(),
                                               'compute.libvirt.error',
                                               payload)
-            raise exception.HypervisorUnavailable(host=CONF.host)
+            raise exception.HypervisorUnavailable()
 
         return conn
 

nova/virt/libvirt/volume/mount.py

@@ -86,7 +86,7 @@ def get_state(self):
         with self.cond:
             state = self.state
             if state is None:
-                raise exception.HypervisorUnavailable(host=CONF.host)
+                raise exception.HypervisorUnavailable()
             self.use_count += 1
 
         try: