CSTACKEX-246: fixing a small error

Author: sathvikaragi

engine/storage/volume/src/main/java/org/apache/cloudstack/storage/volume/VolumeServiceImpl.java

@@ -737,7 +737,7 @@ protected Void managedCopyBaseImageCallback(AsyncCallbackDispatcher<VolumeServic
 
             volume.setPath(templateObjectTo.getPath());
 
-            if (templateObjectTo.getFormat() != null && volume.getFormat() != null) {
+            if (templateObjectTo.getFormat() != null && volume.getFormat() == null) {
                 volume.setFormat(templateObjectTo.getFormat());
             }