Update protobuf to 2.4.1

Change-Id: I0274b3209a23bdb4b3863ecc35145046e3138d30
diff --git a/pom.xml b/pom.xml
index c3caa7d..09bd051 100644
--- a/pom.xml
+++ b/pom.xml
@@ -334,7 +334,7 @@
     <dependency>
       <groupId>com.google.protobuf</groupId>
       <artifactId>protobuf-java</artifactId>
-      <version>2.3.0</version>
+      <version>2.4.1</version>
       <scope>provided</scope>
     </dependency>
   </dependencies>