Revert "Set idle timeouts for HTTP reads and writes in communications with the registry"

This reverts commit 84b2162c1a15256ac09396ad0d75686ea468f40c.

The intent of this commit was to set an idle timeout on a HTTP
connection. If a read took more than 60 seconds to complete, or a write
took more than 60 seconds to complete, the connection would be
considered dead.

This doesn't work properly, because the HTTP internals apparently read
from the connection concurrently while writing. An upload that doesn't
complete in 60 seconds leads to a timeout.

Fixes #19967

Signed-off-by: Aaron Lehmann <aaron.lehmann@docker.com>