Fix croneval script to respect CONF_DIR

This commit fixes the croneval script to respect the CONF_DIR
environment variable used to locate the configuration directory.

Original commit: elastic/x-pack-elasticsearch@79974947f9

plugin/bin/x-pack/croneval

@@ -76,6 +76,10 @@ fi
 
 declare -a args=("$@")
 
+if [ -e "$CONF_DIR" ]; then
+  args=("${args[@]}" --path.conf "$CONF_DIR")
+fi
+
 cd "$ES_HOME" > /dev/null
 "$JAVA" $ES_JAVA_OPTS -cp "$ES_CLASSPATH" -Des.path.home="$ES_HOME" org.elasticsearch.xpack.watcher.trigger.schedule.tool.CronEvalTool "${args[@]}"
 status=$?