remove extra newline in nanny debug output

Signed-off-by: Olaf Hering <olaf@aepfle.de>
Check return value instead of input in ni_dbus_connection_call

Signed-off-by: Olaf Hering <olaf@aepfle.de>
Merge pull request #372 from olafhering/olh-misc

remove extra newline in nanny debug output