commit aac1b06c1e3b0d73ca964794bab0c444d454ebcc
Author: Yasuhiro Matsumoto mattn.jp@gmail.com
Date: Thu May 11 18:40:13 2017 +0900
don't run command when the port is empty
Test::TCP do hack on Windows for checking port used.
https://github.com/tokuhirom/Test-TCP/commit/0f4510d8
But this way always return 0 with succeeded with empty port. This is not
expected behavior. So this change fix to call check_port if the port is
not defined.
fixes #60