webadmin : Hide "CPU Architecture" from New/Edit Cluster popup

Hide "CPU Architecture" from New/Edit Cluster popup

Change-Id: I29868be419437622f37e890e4832db55b1695122
Bug-Url: https://bugzilla.redhat.com/show_bug.cgi?id=1097082
Signed-off-by: Anmol Babu <anbabu@redhat.com>