Fix the error trap, so that it is setup before acquiring the lockfile.

Scripts/developer_scripts/autotest_cgal_with_cmake

@@ -858,6 +858,9 @@ else
   MAKE_CMD='make'
 fi
 
+# that line makes the script remove the lock file in case of unwanted exit
+trap "rm -f $LOCK_FILE" EXIT HUP INT TERM
+
 # Acquire lock
 lockfile -r 5 "$LOCK_FILE";
 if [ ${?} != 0 ]; then
@@ -865,9 +868,6 @@ if [ ${?} != 0 ]; then
   exit 1;
 fi
 
-# that line makes the script remove the lock file in case of unwanted exit
-trap "rm -f $LOCK_FILE" EXIT HUP INT TERM
-
 # Notify test started
 if [ ! "${MAIL_ADDRESS}" = "must_be_set_in_.autocgalrc" ]; then
   for i in ${MAIL_ADDRESS}; do