Bug 826122: Provide meaningful error message if pairing is refused [r=kaze,ehung]

Bluetooth peer devices can refuse to pair if the initiator tries too
often. In this case we now print a more meaningful error message.

Signed-off-by: Thomas Zimmermann <tdz@users.sourceforge.net>
Merge pull request #7425 from tdz/bug-826122

Bug 826122: Provide meaningful error message if pairing is refused [r=kaze,ehung]