Clear the X server lock in the standalone images

Author: enolan

Standalone/entry_point.sh

@@ -14,6 +14,9 @@ if [ ! -z "$SE_OPTS" ]; then
 fi
 
 SERVERNUM=$(get_server_num)
+
+rm -f /tmp/.X*lock
+
 xvfb-run -n $SERVERNUM --server-args="-screen 0 $GEOMETRY -ac +extension RANDR" \
   java ${JAVA_OPTS} -jar /opt/selenium/selenium-server-standalone.jar \
   ${SE_OPTS} &