Silence content type error for external spiget resources (#1431)

scripts/start-spiget

@@ -88,7 +88,7 @@ downloadResourceFromSpiget() {
   resource=${1?}
 
   resourceUrl="https://api.spiget.org/v2/resources/${resource}"
-  if ! outfile=$(get --output-filename -o /tmp "${acceptArgs[@]}" "${resourceUrl}/download"); then
+  if ! outfile=$(get_silent --output-filename -o /tmp "${acceptArgs[@]}" "${resourceUrl}/download"); then
     log "ERROR: failed to download resource '${resource}' from ${resourceUrl}/download"
     if externalUrl=$(get --json-path '$.file.externalUrl' "${resourceUrl}"); then
       log "       Visit $externalUrl to pre-download the resource"

scripts/start-utils

@@ -197,6 +197,14 @@ function get() {
   mc-image-helper "${flags[@]}" get "$@"
 }
 
+function get_silent() {
+  local flags=(-s)
+  if isTrue "${DEBUG_GET:-false}"; then
+    flags+=("--debug")
+  fi
+  mc-image-helper "${flags[@]}" get "$@"
+}
+
 function isFamily() {
   for f in "${@}"; do
     if [[ ${FAMILY^^} == "${f^^}" ]]; then