Enable checkstyle check for blocks without braces.

Enable the checkstyle rule to check for block statements
without curly braces and fix any violations it finds.

Change-Id: Id4c58cea26f0d9ce7ed78643a4943c042886a12d
diff --git a/src/main/java/net/onrc/onos/core/util/IPv4.java b/src/main/java/net/onrc/onos/core/util/IPv4.java
index b25099a..0b5c081 100644
--- a/src/main/java/net/onrc/onos/core/util/IPv4.java
+++ b/src/main/java/net/onrc/onos/core/util/IPv4.java
@@ -47,9 +47,10 @@
      */
     public IPv4(String value) {
         String[] splits = value.split("\\.");
-        if (splits.length != 4)
+        if (splits.length != 4) {
             throw new IllegalArgumentException("Specified IPv4 address must contain four " +
                     "numerical digits separated by '.'");
+        }
 
         int result = 0;
         for (int i = 0; i < 4; ++i) {