Fix samples build file for mobilewebapp target

Review at http://gwt-code-reviews.appspot.com/1449809


git-svn-id: https://google-web-toolkit.googlecode.com/svn/trunk@10254 8db76d5a-ed1c-0410-87a9-c151d255dfc7
diff --git a/samples/build.xml b/samples/build.xml
index fffd2dd..f735d99 100644
--- a/samples/build.xml
+++ b/samples/build.xml
@@ -35,7 +35,7 @@
   </target>
 
   <target name="mobilewebapp" description="Build mobile web app">
-    <gwt.ant dir="mobilewebapp" target="source+libs" />
+    <gwt.ant dir="mobilewebapp" target="source" />
   </target>
 
   <target name="showcase" description="Build showcase">