fix up build paths
diff --git a/releng.control/checkout.xml b/releng.control/checkout.xml
index 7ffa636..90a827c 100644
--- a/releng.control/checkout.xml
+++ b/releng.control/checkout.xml
@@ -228,7 +228,7 @@
             is fetched to control the rest of the build -->
         <property file="${codir}/${env.RELENG}/maps/build.cfg" />
         <delete
-            dir="${codir}/releng.wtpbuilder"
+            dir="${codir}/${env.RELENGWTPBUILDER}"
             failonerror="false" />
         <echo
             message="Version tag for ${env.RELENGWTPBUILDER} is: ${wtpBuilderVersion}" />