also display version number when build is stable (or not)

git-svn-id: http://lampsvn.epfl.ch/svn-repos/scala/scala/trunk@8034 5e8d7ff9-d8ef-0310-90f0-a4852d11357a

build.xml

@@ -637,12 +637,12 @@ TEST
     <delete quiet="yes" failonerror="no">
       <fileset dir="${strap.dir}" includes="**/*.MD5"/>
     </delete>
-    <fail message="Build is not stable">
+    <fail message="Build ${version.number} is not stable">
       <condition><not>
         <equals arg1="${quick.md5}" arg2="${strap.md5}"/>
       </not></condition>
     </fail>
-    <echo level="info" message="Build is stable."/>
+    <echo level="info" message="Build ${version.number} is stable."/>
   </target>
 
   <target name="test.strap" depends="build.strap">