Revert "Add --dnsslowrate arg"

This reverts commit 16db9a7337.

acme.sh

@@ -3974,16 +3974,9 @@ $_authorizations_map"
             return 1
           fi
 
-          if [ "$addcommand" = "dns_aws_add" -a -n "$_dnsslowrate" ] ; then
-            if ! $addcommand "$txtdomain" "$txt" "$_dnsslowrate"; then
-              _err "Error add txt for domain:$txtdomain"
-              return 1
-            fi
-          else
-            if ! $addcommand "$txtdomain" "$txt"; then
-              _err "Error add txt for domain:$txtdomain"
-              return 1
-            fi
+          if ! $addcommand "$txtdomain" "$txt"; then
+            _err "Error add txt for domain:$txtdomain"
+            return 1
           fi
         )
 
@@ -5926,7 +5919,6 @@ _process() {
   _httpport=""
   _tlsport=""
   _dnssleep=""
-  _dnsslowrate=""
   _listraw=""
   _stopRenewOnError=""
   #_insecure=""
@@ -6166,12 +6158,6 @@ _process() {
           _webroot="$_webroot,$wvalue"
         fi
         ;;
-
-      --dnsslowrate)
-        _dnsslowrate="$2"
-        shift
-        ;;
-
       --dnssleep)
         _dnssleep="$2"
         Le_DNSSleep="$_dnssleep"