kvm: Set RAW format to RBD DATADISK (#5801)

While deploying a VM with data disk on Ceph the volume format was in
QCOW2.

Fixes #5531

Author: slavkap

plugins/hypervisors/kvm/src/main/java/com/cloud/hypervisor/kvm/storage/KVMStorageProcessor.java

@@ -1463,7 +1463,7 @@ public Answer createVolume(final CreateObjectCommand cmd) {
             primaryPool = storagePoolMgr.getStoragePool(primaryStore.getPoolType(), primaryStore.getUuid());
             disksize = volume.getSize();
             PhysicalDiskFormat format;
-            if (volume.getFormat() == null) {
+            if (volume.getFormat() == null || StoragePoolType.RBD.equals(primaryStore.getPoolType())) {
                 format = primaryPool.getDefaultFormat();
             } else {
                 format = PhysicalDiskFormat.valueOf(volume.getFormat().toString().toUpperCase());