Don't copy gzipped push files into the project so you can modify the .js files

Change-Id: I9c580a16acb8b2ceef2872c6d043a8a07a9909fe

build/ide.xml

         <property name="js.output.dir" location="WebContent" />
         <property name="push.js.dir" location="${basedir}/push/result/js" />
         <copy todir="${js.output.dir}">
-            <fileset dir="${push.js.dir}" includes="VAADIN/vaadinPush*">
+            <fileset dir="${push.js.dir}" includes="VAADIN/vaadinPush*" excludes="**/*.gz">
             </fileset>
         </copy>
     </target>