Ensure both input and output baud rates are set.

QSerialPortPrivate::setBaudRate() wasn't trying to set the output
baud rate for the port after successfully setting the input baud rate.

Also, some devices (such as FTDI chips) on Mac don't respond
properly if you call updateTermios() with mismatched baud rates,
even if you later set them to be the same.

Change-Id: I507fe10cba221bb4e43ded650dc44cc974de2414
Reviewed-by: Sergey Belyashov <Sergey.Belyashov@gmail.com>
Reviewed-by: Laszlo Papp <lpapp@kde.org>
Merge remote-tracking branch 'origin/release' into stable

Change-Id: I26db36a638685472296001d9982a157b8a6616b5
Merge "Merge remote-tracking branch 'origin/release' into stable" into refs/staging/stable
Use Q_NULLPTR for null pointer purposes with NULL fallback for Qt 4

Change-Id: I5422376a26111f7c8e084791a059215238a16868
Reviewed-by: Sergey Belyashov <Sergey.Belyashov@gmail.com>
Reviewed-by: Steven Ceuppens <steven.ceuppens@icloud.com>
Reviewed-by: Denis Shienkov <denis.shienkov@gmail.com>