Enable debug output for failing mvn command

Author: mickaelistria

Jenkinsfile

@@ -69,7 +69,7 @@ pipeline {
 					unset JAVA_TOOL_OPTIONS
 					unset _JAVA_OPTIONS
 					# force qualifier to start with `z` so we identify it more easily and it always seem more recent than upstrea
-					mvn install -DskipTests -Djava.io.tmpdir=$WORKSPACE/tmp \
+					mvn install -X -DskipTests -Djava.io.tmpdir=$WORKSPACE/tmp \
 						-Dtycho.buildqualifier.format="'z'yyyyMMdd-HHmm" \
 						-Pp2-repo \
 						-pl org.eclipse.jdt.core.compiler.batch,org.eclipse.jdt.core,org.eclipse.jdt.core.javac,org.eclipse.jdt.core.javac.feature,org.eclipse.jdt.core.tests.model,org.eclipse.jdt.core.tests.compiler,repository