Fix some checkstyle and PMD errors in the topology module.

Change-Id: Icf037cefdff18256f1234ed2b6eac761d29af7ac
diff --git a/conf/pmd/onos_ruleset.xml b/conf/pmd/onos_ruleset.xml
index 1a1fae0..7c862a3 100644
--- a/conf/pmd/onos_ruleset.xml
+++ b/conf/pmd/onos_ruleset.xml
@@ -35,6 +35,7 @@
     <rule ref="rulesets/java/braces.xml"/>
     <rule ref="rulesets/java/naming.xml">
       <exclude name="AvoidInstantiatingObjectsInLoops" />
+      <exclude name="ShortClassName" />
       <exclude name="ShortMethodName" />
       <exclude name="ShortVariable" />
       <exclude name="LongVariable" />