Merge pull request rubyzip#325 from aeroastro/feature/tempfile-directory

Save temporary files to a temporary directory

lib/zip/streamable_stream.rb

@@ -5,7 +5,7 @@ def initialize(entry)
       dirname = if zipfile.is_a?(::String)
                   ::File.dirname(zipfile)
                 else
-                  '.'
+                  nil
                 end
       @temp_file = Tempfile.new(::File.basename(name), dirname)
       @temp_file.binmode