fix https://github.com/Neilpang/acme.sh/issues/999

acme.sh

@@ -3934,7 +3934,10 @@ issue() {
   Le_NextRenewTime=$(_math "$Le_NextRenewTime" - 86400)
   _savedomainconf "Le_NextRenewTime" "$Le_NextRenewTime"
 
-  _on_issue_success "$_post_hook" "$_renew_hook"
+  if ! _on_issue_success "$_post_hook" "$_renew_hook"; then
+    _err "Call hook error."
+    return 1
+  fi
 
   if [ "$_real_cert$_real_key$_real_ca$_reload_cmd$_real_fullchain" ]; then
     _savedomainconf "Le_RealCertPath" "$_real_cert"