Reduce SDP discovery debug output on Bluez

Printing the entire SDP xml is just too verbose. This reduces the output
by multiple pages.

Change-Id: I08ffb7799f3c9f5a61de224e58e565719d44b81b
Reviewed-by: Aaron McCarthy <mccarthy.aaron@gmail.com>
Reviewed-by: Alex Blasche <alexander.blasche@digia.com>