ceph: Fixes #2611 use raw disk type for rdb (#2623)

Fix issue where kvm / ceph cannot create volumes. Fixes #2611

Author: nathanejohnson

plugins/hypervisors/kvm/src/com/cloud/hypervisor/kvm/storage/LibvirtStorageAdaptor.java

@@ -661,7 +661,7 @@ public KVMPhysicalDisk createPhysicalDisk(String name, KVMStoragePool pool,
 
         switch (pool.getType()) {
             case RBD:
-                return createPhysicalDiskByLibVirt(name, pool, format, provisioningType, size);
+                return createPhysicalDiskByLibVirt(name, pool, PhysicalDiskFormat.RAW, provisioningType, size);
             case NetworkFilesystem:
             case Filesystem:
                 switch (format) {