Remove obsolete codehaus snapshot repository

Since the gwt-maven plugin we are using is available in Maven
Central, we don't need to be looking at this snapshot repository
to locate the plugin.

Change-Id: Ie23d3e85231a08ae57f9ed9bcdda9274f2c3dbdd
Signed-off-by: Shawn O. Pearce <sop@google.com>
diff --git a/pom.xml b/pom.xml
index 235045b..d3f6dc2 100644
--- a/pom.xml
+++ b/pom.xml
@@ -770,11 +770,4 @@
       <url>http://maven.objectweb.org/maven2/</url>
     </repository>
   </repositories>
-
-  <pluginRepositories>
-    <pluginRepository>
-      <id>gwt-maven-plugins</id>
-      <url>http://snapshots.repository.codehaus.org/</url>
-    </pluginRepository>
-  </pluginRepositories>
 </project>