Fix missing HTTP_HEADER for _get with wget

Save http header to file for _get with wget.

acme.sh

@@ -2054,7 +2054,7 @@ _get() {
     if [ "$onlyheader" ]; then
       $_WGET --user-agent="$USER_AGENT" --header "$_H5" --header "$_H4" --header "$_H3" --header "$_H2" --header "$_H1" -S -O /dev/null "$url" 2>&1 | sed 's/^[ ]*//g'
     else
-      $_WGET --user-agent="$USER_AGENT" --header "$_H5" --header "$_H4" --header "$_H3" --header "$_H2" --header "$_H1" -O - "$url"
+      $_WGET --user-agent="$USER_AGENT" --header "$_H5" --header "$_H4" --header "$_H3" --header "$_H2" --header "$_H1" -S -O - "$url" 2>"$HTTP_HEADER"
     fi
     ret=$?
     if [ "$ret" = "8" ]; then