chore: remove ruby warning about unused variable

lib/mini_portile2/mini_portile.rb

@@ -473,7 +473,6 @@ def download_file(url, full_path, count = 3)
   def download_file_http(url, full_path, count = 3)
     filename = File.basename(full_path)
     with_tempfile(filename, full_path) do |temp_file|
-      progress = 0
       total = 0
       params = {
         "Accept-Encoding" => 'identity',
@@ -482,7 +481,6 @@ def download_file_http(url, full_path, count = 3)
           if total
             new_progress = (bytes * 100) / total
             message "\rDownloading %s (%3d%%) " % [filename, new_progress]
-            progress = new_progress
           else
             # Content-Length is unavailable because Transfer-Encoding is chunked
             message "\rDownloading %s " % [filename]
@@ -532,14 +530,12 @@ def download_file_file(uri, full_path)
   def download_file_ftp(uri, full_path)
     filename = File.basename(uri.path)
     with_tempfile(filename, full_path) do |temp_file|
-      progress = 0
       total = 0
       params = {
         :content_length_proc => lambda{|length| total = length },
         :progress_proc => lambda{|bytes|
           new_progress = (bytes * 100) / total
           message "\rDownloading %s (%3d%%) " % [filename, new_progress]
-          progress = new_progress
         }
       }
       if ENV["ftp_proxy"]