Fix Sonar issue:

Strings literals should be placed on the left side when checking for
equality

Change-Id: I4537e08936731ace55aeecb3ad941269ec1eb191
diff --git a/apps/vtn/sfcmgr/src/main/java/org/onosproject/sfc/manager/impl/SfcManager.java b/apps/vtn/sfcmgr/src/main/java/org/onosproject/sfc/manager/impl/SfcManager.java
index eb63917..d429fc9 100644
--- a/apps/vtn/sfcmgr/src/main/java/org/onosproject/sfc/manager/impl/SfcManager.java
+++ b/apps/vtn/sfcmgr/src/main/java/org/onosproject/sfc/manager/impl/SfcManager.java
@@ -407,11 +407,11 @@
                     boolean match = false;
                     // Check whether protocol is set in flow classifier
                     if (flowClassifier.protocol() != null) {
-                        if ((flowClassifier.protocol().equalsIgnoreCase("TCP")
+                        if (("TCP".equalsIgnoreCase(flowClassifier.protocol())
                                 && fiveTuple.protocol() == IPv4.PROTOCOL_TCP)
-                                || (flowClassifier.protocol().equalsIgnoreCase("UDP")
+                                || ("UDP".equalsIgnoreCase(flowClassifier.protocol())
                                         && fiveTuple.protocol() == IPv4.PROTOCOL_UDP)
-                                        || (flowClassifier.protocol().equalsIgnoreCase("ICMP")
+                                        || ("ICMP".equalsIgnoreCase(flowClassifier.protocol())
                                                 && fiveTuple.protocol() == IPv4.PROTOCOL_ICMP)) {
                             match = true;
                         } else {