Fix Sonar issue:

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

Change-Id: I4537e08936731ace55aeecb3ad941269ec1eb191
diff --git a/apps/faultmanagement/fmmgr/src/test/java/org/onosproject/faultmanagement/impl/PollingAlarmProviderTest.java b/apps/faultmanagement/fmmgr/src/test/java/org/onosproject/faultmanagement/impl/PollingAlarmProviderTest.java
index 3074dd5..b96af16 100644
--- a/apps/faultmanagement/fmmgr/src/test/java/org/onosproject/faultmanagement/impl/PollingAlarmProviderTest.java
+++ b/apps/faultmanagement/fmmgr/src/test/java/org/onosproject/faultmanagement/impl/PollingAlarmProviderTest.java
@@ -298,7 +298,7 @@
 
         @Override
         public Object get(Object key) {
-            if (key.equals("pollFrequency")) {
+            if ("pollFrequency".equals(key)) {
                 return "1";
             }
             return null;