Use ${*} instead of ${@} for checking for no arguments in lh_clean.

${@} expands to "<arg1>" "<arg2>" ... etc., which causes the -z test to
encounter too many arguments and thus fail with an error.

Signed-off-by: Chris Lamb <chris@chris-lamb.co.uk>

helpers/lh_clean

@@ -42,7 +42,7 @@ fi
 
 rm -f .lock
 
-if [ -z "${@}" ]
+if [ -z "${*}" ]
 then
 	ARGUMENTS="--all"
 else