Initialize QBluetoothSocket::socketError properly.

So far the initial value is compiler dependent. In most cases this meant
it was set to 0. However 0 is not even a valid
QBluetoothSocket::SocketError enum value. The NoSocketError value is -2.

Change-Id: Ieee4f7bd1c97d758295f4d0cc1297f62c114f4f3
Reviewed-by: Fabian Bumberger <fbumberger@rim.com>
Refine documentation for QBluetoothSocket::localXYZ() functions.

Bluez never returns anything until the connection has been established.
BlackBerry and the future Android port are much quicker.

Change-Id: Ic465a9b68176e7fff5f0c88b4fb602f8665f7197
Reviewed-by: Fabian Bumberger <fbumberger@rim.com>