Simplify the implementation of equals() method.

Change-Id: I2b3ea911643a9d8ef841f0338084b4e673888c2d
diff --git a/src/main/java/net/onrc/onos/api/flowmanager/Flow.java b/src/main/java/net/onrc/onos/api/flowmanager/Flow.java
index 8fe9577..6ea85a1 100644
--- a/src/main/java/net/onrc/onos/api/flowmanager/Flow.java
+++ b/src/main/java/net/onrc/onos/api/flowmanager/Flow.java
@@ -67,7 +67,7 @@
         if (this == obj) {
             return true;
         }
-        if ((obj == null) || !(obj instanceof Flow)) {
+        if (!(obj instanceof Flow)) {
             return false;
         }
         Flow other = (Flow) obj;