Fix legacy link key storing for some buggy adapters
Fix legacy link key storing for some buggy adapters

Some adapters seem to generate in some circumstances a changed
combination key even though there is no existing key for the link. In
order to properly store the key this patch fixes the code to set the
correct key type (0x00) for this situation. The hcidump below is from a
Broadcom 2.1 adapter connecting to a pre-2.1 Jabra headset (with
irrelevant commands & events excluded):

< HCI Command: Create Connection (0x01|0x0005) plen 13
    bdaddr 00:13:17:xx:xx:xx ptype 0xcc18 rswitch 0x01 clkoffset 0x0000
    Packet type: DM1 DM3 DM5 DH1 DH3 DH5
> HCI Event: Command Status (0x0f) plen 4
    Create Connection (0x01|0x0005) status 0x00 ncmd 1
> HCI Event: Connect Complete (0x03) plen 11
    status 0x00 handle 11 bdaddr 00:13:17:xx:xx:xx type ACL encrypt 0x00
< HCI Command: Read Remote Supported Features (0x01|0x001b) plen 2
    handle 11
> HCI Event: Command Status (0x0f) plen 4
    Read Remote Supported Features (0x01|0x001b) status 0x00 ncmd 1
> HCI Event: Read Remote Supported Features (0x0b) plen 11
    status 0x00 handle 11
    Features: 0xbf 0xfe 0x8b 0x78 0x18 0x18 0x00 0x80
< ACL data: handle 11 flags 0x02 dlen 10
    L2CAP(s): Info req: type 2
< HCI Command: Authentication Requested (0x01|0x0011) plen 2
    handle 11
> HCI Event: Command Status (0x0f) plen 4
    Authentication Requested (0x01|0x0011) status 0x00 ncmd 1
> HCI Event: Link Key Request (0x17) plen 6
    bdaddr 00:13:17:xx:xx:xx
< HCI Command: Link Key Request Negative Reply (0x01|0x000c) plen 6
    bdaddr 00:13:17:xx:xx:xx
> HCI Event: Command Complete (0x0e) plen 10
    Link Key Request Negative Reply (0x01|0x000c) ncmd 1
    status 0x00 bdaddr 00:13:17:xx:xx:xx
> HCI Event: PIN Code Request (0x16) plen 6
    bdaddr 00:13:17:xx:xx:xx
< HCI Command: PIN Code Request Reply (0x01|0x000d) plen 23
    bdaddr 00:13:17:xx:xx:xx len 4 pin '0000'
> HCI Event: Command Complete (0x0e) plen 10
    PIN Code Request Reply (0x01|0x000d) ncmd 1
    status 0x00 bdaddr 00:13:17:xx:xx:xx
> HCI Event: Link Key Notification (0x18) plen 23
    bdaddr 00:13:17:xx:xx:xx key 4DC4AF33C8D5D694B33FAA439B031D67 type 6
    Type: Changed Combination Key
> HCI Event: Auth Complete (0x06) plen 3
    status 0x00 handle 11

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