Enable checkstyle rule to catch inner assignments.

Turn on the checkstyle rule that catches assignemnts used as
expressions and fix the violations that it detects.

Change-Id: I8f0ddfdd401f247523e98d7359872a8b4a367106
diff --git a/conf/checkstyle/sun_checks.xml b/conf/checkstyle/sun_checks.xml
index 18f5929..aa19cec 100644
--- a/conf/checkstyle/sun_checks.xml
+++ b/conf/checkstyle/sun_checks.xml
@@ -220,10 +220,7 @@
         </module>
 
         <module name="IllegalInstantiation"/>
-
-        <module name="InnerAssignment">
-          <property name="severity" value="warning"/>
-        </module>
+        <module name="InnerAssignment"/>
 
         <!-- Many violations of this rule present, revist in a
         subsequent round of cleanups -->
diff --git a/src/main/java/net/onrc/onos/core/devicemanager/OnosDeviceManager.java b/src/main/java/net/onrc/onos/core/devicemanager/OnosDeviceManager.java
index 48e23eb..30ad722 100644
--- a/src/main/java/net/onrc/onos/core/devicemanager/OnosDeviceManager.java
+++ b/src/main/java/net/onrc/onos/core/devicemanager/OnosDeviceManager.java
@@ -132,8 +132,8 @@
         }
 
         //We check if it is the same device in datagrid to suppress the device update
-        OnosDevice exDev = null;
-        if ((exDev = mapDevice.get(mac)) != null) {
+        OnosDevice exDev = mapDevice.get(mac);
+        if (exDev != null) {
             if (exDev.equals(srcDevice)) {
                 //There is the same existing device. Update only ActiveSince time.
                 exDev.setLastSeenTimestamp(new Date());