RANGER-3136: NUllPointException occur when import polices anf isOverride is selected

Signed-off-by: pradeep <pradeep@apache.org>
diff --git a/security-admin/src/main/java/org/apache/ranger/rest/ServiceREST.java b/security-admin/src/main/java/org/apache/ranger/rest/ServiceREST.java
index 8db022e..63ad281 100644
--- a/security-admin/src/main/java/org/apache/ranger/rest/ServiceREST.java
+++ b/security-admin/src/main/java/org/apache/ranger/rest/ServiceREST.java
@@ -2698,7 +2698,8 @@
 			for (int i = 0; i < sourceServices.size(); i++) {
 				if (!destinationServices.get(i).isEmpty() ) {
 					SearchFilter filter = new SearchFilter();
-					filter.setParam("zoneName",zoneName);
+					filter.setParam(SearchFilter.ZONE_NAME, zoneName);
+					filter.setParam(SearchFilter.SERVICE_NAME, destinationServices.get(i));
 					RangerService service=getServiceByName(destinationServices.get(i));
 					final RangerPolicyList servicePolicies = getServicePolicies(destinationServices.get(i),filter);
 					if (servicePolicies != null) {