migrate: use correct grammar

According to http://grammar.quickanddirtytips.com/a-while-awhile.aspx,
you can tell whether to use 'awhile' or 'a while' by substituting
'quietly' or 'a year' and seeing if the resulting sentence still makes
sense.  During migration, we used an adverb, but want the noun form.

* src/virtManager/migrate.py (vmmMigrateDialog.finish): Use
correct grammar.

(crobinso: Add Eric to AUTHORS)

AUTHORS

@@ -158,6 +158,7 @@ Further patches have been submitted by:
     Giuseppe Scrivano <gscrivano@gnu.org>
     Ken ICHIKAWA <ichikawa.ken@jp.fujitsu.com>
     Tom Lanyon <tom@oneshoeco.com>
+    Eric Blake <eblake@redhat.com>
 
     <...send a patch & get your name here...>
 

virtManager/migrate.py

@@ -1,5 +1,5 @@
 #
-# Copyright (C) 2009 Red Hat, Inc.
+# Copyright (C) 2009, 2013 Red Hat, Inc.
 # Copyright (C) 2009 Cole Robinson <crobinso@redhat.com>
 #
 # This program is free software; you can redistribute it and/or modify
@@ -480,7 +480,7 @@ class vmmMigrateDialog(vmmGObjectUI):
                                max_downtime],
                               _("Migrating VM '%s'" % self.vm.get_name()),
                               (_("Migrating VM '%s' from %s to %s. "
-                                 "This may take awhile.") %
+                                 "This may take a while.") %
                                 (self.vm.get_name(), srchost, dsthost)),
                               self.topwin,
                               cancel_back=_cancel_back,