551713 - Switch to old version of Virgo build tools

For more information see:
https://bugs.eclipse.org/bugs/show_bug.cgi?id=551713
diff --git a/buildSrc/src/main/groovy/virgobuild/Constants.groovy b/buildSrc/src/main/groovy/virgobuild/Constants.groovy
index 9225808..f798aa2 100644
--- a/buildSrc/src/main/groovy/virgobuild/Constants.groovy
+++ b/buildSrc/src/main/groovy/virgobuild/Constants.groovy
@@ -7,10 +7,10 @@
     }
 
     static String getVirgoBuildToolsVersion() {
-        return '1.4.1.RELEASE'
+        return '1.2.1.RELEASE'
     }
 
     static URL getVirgoBuildToolsDownloadUrl() {
-        return new URL("http://build.eclipse.org/rt/virgo/zips/release/VB/${virgoBuildToolsVersion}/virgo-build-tools-${virgoBuildToolsVersion}.zip")
+        return new URL("https://mirror.dkm.cz/eclipse/virgo/release/VB/1.2.1/virgo-build-tools-1.2.1.RELEASE.zip")
     }
 }