-revert change as we don't support antlr3 (yet)

git-svn-id: https://svn.apache.org/repos/asf/ant/core/trunk@586652 13f79535-47bb-0310-9956-ffa450edef68

build.xml

@@ -395,12 +395,9 @@
     <available property="commons.net.present"
       classname="org.apache.commons.net.ftp.FTPClient"
       classpathref="classpath"/>
-    <condition property="antlr.present">
-  	  <or>
-  	    <available classname="org.antlr.Tool" classpathref="classpath"/>
-  	    <available classname="antlr.Tool" classpathref="classpath"/>
-      </or>
-  	</condition>
+    <available property="antlr.present" 
+      classname="antlr.Tool" 
+      classpathref="classpath"/>
     <available property="stylebook.present"
       classname="org.apache.stylebook.Engine"
       classpathref="classpath"/>