freerdp: properly fix QA issue

* without x11, wayland, directfb enabled there is no bindir directory
  so the error wasn't about empty /usr/bin/ being unpackaged, but there was
  /usr/bin binary which was winpr-makecert installed above, fix by creating
  the directory first

Signed-off-by: Martin Jansa <Martin.Jansa@gmail.com>