shared/gatt-db: Fix crash on find by type search
shared/gatt-db: Fix crash on find by type search

Make sure all fields in search data are set.
Without this patch we got:

==29603== Conditional jump or move depends on uninitialised value(s)
==29603==    at 0x409689: find_by_type (gatt-db.c:866)
==29603==    by 0x40C1A7: queue_foreach (queue.c:251)
==29603==    by 0x40A341: gatt_db_find_by_type (gatt-db.c:889)
==29603==    by 0x408E8C: init_complete (gatt-client.c:1225)
==29603==    by 0x4073B5: discover_descs_cb (gatt-client.c:690)
==29603==    by 0x40CB1C: discover_descs_cb (gatt-helpers.c:1453)
==29603==    by 0x405445: can_read_data (att.c:600)
==29603==    by 0x40B097: io_callback (io-mainloop.c:123)
==29603==    by 0x40BA3B: mainloop_run (mainloop.c:142)
==29603==    by 0x401FD7: main (btgatt-client.c:1269)

pstglia/external-bluetooth-bluez,pkarasev3/bluez,ComputeCycles/bluez,pstglia/external-bluetooth-bluez,pkarasev3/bluez,ComputeCycles/bluez,mapfau/bluez,pkarasev3/bluez,silent-snowman/bluez,mapfau/bluez,ComputeCycles/bluez,silent-snowman/bluez,pstglia/external-bluetooth-bluez,ComputeCycles/bluez,silent-snowman/bluez,mapfau/bluez,pkarasev3/bluez,silent-snowman/bluez,pstglia/external-bluetooth-bluez,mapfau/bluez