Update checkstyle version.

- Removing explicitly specifying checkstyle version.
   Checkstyle bundled with the maven plugin now supports Java 8.
   Also version previously specified could not parse "Hash<T>::new"
- RedundantThrows was removed from recent checkstyle:
   See: https://github.com/checkstyle/checkstyle/issues/473

Change-Id: Ic6301b1900edd9e1ad704e206185c2677814fcd7

@@ -691,12 +691,6 @@
                         <artifactId>onos-build-conf</artifactId>
                         <artifactId>onos-build-conf</artifactId>
                         <version>${onos-build-conf.version}</version>
                         <version>${onos-build-conf.version}</version>
                     </dependency>
                     </dependency>
-                    <!-- For Java 8 lambda support-->
-                    <dependency>
-                        <groupId>com.puppycrawl.tools</groupId>
-                        <artifactId>checkstyle</artifactId>
-                        <version>5.9</version>
-                    </dependency>
                 </dependencies>
                 </dependencies>
                 <configuration>
                 <configuration>
                     <!-- begin: workaround for unexpected NullPointerException on Eclipse -->
                     <!-- begin: workaround for unexpected NullPointerException on Eclipse -->

@@ -257,10 +257,6 @@
         <!-- <module name="MagicNumber"/> -->
         <!-- <module name="MagicNumber"/> -->
         <module name="MissingSwitchDefault"/>
         <module name="MissingSwitchDefault"/>
 
 
-        <module name="RedundantThrows">
-            <property name="allowSubclasses" value="true"/>
-        </module>
-
         <module name="SimplifyBooleanExpression"/>
         <module name="SimplifyBooleanExpression"/>
         <module name="SimplifyBooleanReturn"/>
         <module name="SimplifyBooleanReturn"/>