common: Properly forward arguments from die to error

Also allow this function to be called without arguments, in which case,
don't call error at all. Some uses of this function wrongly assumed
that this was already allowed.

Signed-off-by: Dave Reisner <dreisner@archlinux.org>
Signed-off-by: Pierre Schmitz <pierre@archlinux.de>

lib/common.sh

@@ -82,7 +82,7 @@ trap_exit() {
 }
 
 die() {
-	error "$*"
+	(( $# )) && error "$@"
 	cleanup 1
 }