safety net, change to starting directory nefore rm'ing self-generated stuff

releng/releng_build_isojigdo

@@ -2,11 +2,12 @@
 
 set -e
 
-# required
+START_DIR=`pwd`
+# required config items
 XOR=""
 DIR=""
 IMG=""
-# optional
+# optional config items
 ISOLINUX_BIN=""
 BOOT_CAT=""
 CONFFILE=$HOME/releng_build_isojigdo.conf
@@ -146,6 +147,9 @@ esac
 
 # sort out the cruft
 if [ ${CLEAN} -eq 1 ]; then
+ # safety net, just in case -> we want to be in the starting
+ # directory before removing whatever self-generated stuff
+ cd "${START_DIR}" || exit 1
  rm -f ${RES}
  printf "$0: removed %s\n" ${RES}
 else