Replace Stream#forEach() with Collection#forEach()

Change-Id: I2b261c3d91d345907b165bd61eb7b6c45011c247
diff --git a/apps/openstacknetworking/routing/src/main/java/org/onosproject/openstacknetworking/routing/OpenstackPnatHandler.java b/apps/openstacknetworking/routing/src/main/java/org/onosproject/openstacknetworking/routing/OpenstackPnatHandler.java
index 9431e4f..234e9ce 100644
--- a/apps/openstacknetworking/routing/src/main/java/org/onosproject/openstacknetworking/routing/OpenstackPnatHandler.java
+++ b/apps/openstacknetworking/routing/src/main/java/org/onosproject/openstacknetworking/routing/OpenstackPnatHandler.java
@@ -315,7 +315,7 @@
         }
 
         tBuilder.setIpSrc(externalIp);
-        gatewayService.getGatewayNodes().stream().forEach(gateway -> {
+        gatewayService.getGatewayNodes().forEach(gateway -> {
             TrafficTreatment.Builder tmpBuilder = DefaultTrafficTreatment.builder(tBuilder.build());
             tmpBuilder.setOutput(gatewayService.getUplinkPort(gateway.getGatewayDeviceId()));
             ForwardingObjective fo = DefaultForwardingObjective.builder()
@@ -374,7 +374,7 @@
             return;
         }
 
-        gatewayService.getGatewayDeviceIds().stream().forEach(deviceId -> {
+        gatewayService.getGatewayDeviceIds().forEach(deviceId -> {
             DeviceId srcDeviceId = srcVm.get().location().deviceId();
             TrafficTreatment.Builder tmpBuilder = DefaultTrafficTreatment.builder(tBuilder.build());
             tmpBuilder.extension(RulePopulatorUtil.buildExtension(
@@ -431,4 +431,4 @@
             }
         }
     }
-}
\ No newline at end of file
+}