Setup an error when QSP::setBaudRate() fails on Unix

Inside of a method is missed setup of an error code, therefore always
returns QSP::UnknownError (or some previous error).

Tested on Linux with USB PL2303, using Terminal example (when trying to
setup of an unsupported 14400 baud rate).

Change-Id: I6b3143dd6d451a32024a5ca5239dac826ceb7af6
Reviewed-by: Denis Shienkov <denis.shienkov@gmail.com>
Detect of Bluetooth SPP (rfcomm) device with SysFs

Change-Id: I41d67e9ca8d9cb6042b4d8de756a22d18b077dcd
Reviewed-by: Denis Shienkov <denis.shienkov@gmail.com>