Add update.properties file to com.google.dart.tools.core_*.jar file

dart/editor/tools/features/com.google.dart.tools.deploy.feature_releng/build_rcp.xml

 <!--
 This build script will build the Dart RCP and Dart update site.
 
 This script will setup the PDE build structure and then call into the PDE
 build system.  The PDE build system has to run under Eclipse.
 -->
 <project name="build_dart" default="build_rcp">
 
     <import file="build-common.xml" />
 
@@ skipping 137 matching lines @@
 
         <mkdir dir="${build.runtime}" />
         <mkdir dir="${build.target}" />
         <mkdir dir="${build.stage.plugins}" />
         <mkdir dir="${build.stage.features}" />
         <mkdir dir="${build.out}" />
 
         <property name="build.dart.sdk" value="true"/>
 
         <echoProperty propertyname="build.revision" />
+        <echoProperty propertyname="build.channel" />
         <echoProperty propertyname="build.builder" />
         <echoProperty propertyname="build.root" />
         <echoProperty propertyname="build.out" />
         <echoProperty propertyname="build.source" />
         <echoProperty propertyname="build.source.root"/>
         <echoProperty propertyname="build.out.property.file" />
         <echoProperty propertyname="build.os" />
         <echoProperty propertyname="build.dart.sdk.zip" />
         <echoProperty propertyname="build.download.sdk" />
     </target>
@@ skipping 201 matching lines @@
             <include name="build.properties" />
             <replacefilter token="@BUILDCONFIGS@" value="${build.configs}" />
         </replace>
 
         <replace dir="${build.stage.plugins}/com.google.dart.tools.core" >
             <include name="**/DartCore.java" />
             <replacefilter token="@BUILDDATE@" value="${build.date.ymd}" />
             <replacefilter token="@REVISION@" value="${build.revision}" />
         </replace>
 
+        <echo message="replacing @CHANNEL@ in ${build.stage.plugins}/com.google.dart.tools.core/update.properties" />
+        <replace dir="${build.stage.plugins}/com.google.dart.tools.core" >
+            <include name="update.properties" />
+            <replacefilter token="@CHANNEL@" value="${build.channel}" />
+        </replace>
+
         <echo message="replacing @BUILDYEAR@ in ${build.stage.plugins}/com.google.dart.tools.ui/src/com/google/dart/tools/ui/dialogs/DialogsMessages.properties" />
         <replace dir="${build.stage.plugins}/com.google.dart.tools.ui" summary="true">
             <include name="**/ui/dialogs/*.properties" />
             <replacefilter token="@BUILDYEAR@" value="${build.year}" />
         </replace>
 
         <replace dir="${build.stage.features}">
             <include name="**/feature.xml"/>
             <replacefilter token="0.0.1.qualifier" value="${dart.version}.qualifier" />
             <replacefilter token="0.0.0.qualifier" value="${dart.version}.qualifier" />
@@ skipping 78 matching lines @@
 }</echo>
     </target>
 
     <!-- - - - - - - - - - - - - - - - - -
           target: doDeploy_rcp
          - - - - - - - - - - - - - - - - - -->
     <target name="doDeploy_rcp" depends="init, setupBuild, doBuild_rcp, package_rcp">
     </target>
 
 </project>