Fixes for Windows Serial Port.

Cleaned up some error messages. Especially when a system has no
serial ports. Also added a delay when ports are closed since some
serial port drivers (FDTI in particular) take a bit longer to
properly close. Especially important in pause situations where we
want to use the serial port for some other purpose right away.

Change-Id: Ifc9b7171682962e0aed8e9ed9ebf5472fc9e8206
(cherry picked from commit db3d5974e66ac443ee773e062f62fe8537933f3c)
5 files changed