Fix bug with 3PAR host entry in wrong domain

This patch exposes a more acurate exception message
when a user has created a manual host entry on a
3PAR system that is in an incorrect 3PAR domain than
the domain that is configured for the 3PAR driver.

The bug complained that it couldn't find a VLUN, when the
actual problem was the host existed in the wrong 3PAR domain.

Fixes bug #1158991

Change-Id: I3f92e59ae43a10a0788d97d987785b6520f9f1be

cinder/exception.py

@@ -474,6 +474,10 @@ class Duplicate3PARHost(CinderException):
     message = _("3PAR Host already exists: %(err)s.  %(info)s")
 
 
+class Invalid3PARDomain(CinderException):
+    message = _("Invalid 3PAR Domain: %(err)s")
+
+
 class VolumeTypeCreateFailed(CinderException):
     message = _("Cannot create volume_type with "
                 "name %(name)s and specs %(extra_specs)s")