Fix bluetoothd crash in discover_services_reply()

Fix bluetoothd crash in discover_services_reply()

This patch fixes bluetoothd crash in discover_services_reply while
handling sdp browse results if results contains invalid utf8
charactors.

Crash call stack is given below for reference:
0  0xb6ab8094 in raise () from /lib/libc.so.6
1  0xb6ab93f0 in abort () from /lib/libc.so.6
2  0xb6d30250 in ?? () from /lib/libdbus-1.so.3
3  0xb6d29754 in _dbus_warn_check_failed () from /lib/libdbus-1.so.3
4  0xb6d1f8a4 in dbus_message_iter_append_basic () from /lib/libdbus-1.so.3
5  0xb6eccc60 in iter_append_record () at src/device.c:3285
6  discover_services_reply () at src/device.c:3338
7  0xb6ed303c in search_cb () at src/device.c:6657
8  browse_cb () at src/device.c:6695
9  0xb6eae54a in search_completed_cb () at src/sdp-client.c:205
10 0xb6edf77a in sdp_process () at lib/sdp.c:4354
...

Change-Id: Id11dff0f2304f7e3dc6cd645b3418382744b1759
Signed-off-by: Atul Rai <a.rai@samsung.com>