[rubygems/rubygems] Improve gzip errors logging

By default, the `Zlib::GzipFile::Error` does not include the actual data
that was not in gzip format that caused the error.

However, its `#inspect` method includes it.

I think this can be helpful to troubleshoot errors.

https://github.com/rubygems/rubygems/commit/11c8717133

lib/rubygems/util.rb

@@ -11,7 +11,13 @@ module Gem::Util
     require 'stringio'
     data = StringIO.new(data, 'r')
 
-    unzipped = Zlib::GzipReader.new(data).read
+    gzip_reader = begin
+                    Zlib::GzipReader.new(data)
+                  rescue Zlib::GzipFile::Error => e
+                    raise e.class, e.inspect, e.backtrace
+                  end
+
+    unzipped = gzip_reader.read
     unzipped.force_encoding Encoding::BINARY
     unzipped
   end