Releng: try to use base location for second phase

(was mismatching variant vs. launcher version)
diff --git a/releng/build-scripts/build/run.xml b/releng/build-scripts/build/run.xml
index 324d7c8..496a72e 100644
--- a/releng/build-scripts/build/run.xml
+++ b/releng/build-scripts/build/run.xml
@@ -287,7 +287,7 @@
 			dir="${bootLocation}" 
 			fork="true" 
 			classname="org.eclipse.equinox.launcher.Main"
-			classpath="${bootLocation}/plugins/${org.eclipse.equinox.launcher_jar}">
+			classpath="${baseLocation}/plugins/${org.eclipse.equinox.launcher_jar}">
 				<arg value="-clean"/>
 				<arg value="-Dosgi.ws=${ws}"/>
 				<arg value="-Dosgi.os=${os}"/>