make arguments to _mktemp optional (fixes #178)

diff --git a/letsencrypt.sh b/letsencrypt.sh
index 6606ac322db369eed41ae06fbb46e96a256156a9..44e6c2986726a35403fd7ff07ed678cb5be09ab4 100755 (executable)
--- a/letsencrypt.sh
+++ b/letsencrypt.sh
@@ -24,7 +24,8 @@ BASEDIR="${SCRIPTDIR}"
 
 # Create (identifiable) temporary files
 _mktemp() {
-  mktemp -t letsencrypt.sh-XXXXXX "${@}"
+  # shellcheck disable=SC2068
+  mktemp -t letsencrypt.sh-XXXXXX ${@:-}
 }
 
 # Check for script dependencies