hfp_hf_bluez5: Fix re-registering a modem for a device

Even for outgoing pairing requests we may receive the UUIDs property
changed after the device is paired and try to register it twice.

The easiest way to reproduce this is when Extended Inquiry Response is
supported.

When the device is paired, we receive the "Paired" PropertyChanged,
inside modem_register_from_proxy(), g_dbus_proxy_get_property() gets
the UUIDs extracted from the EIR data.  Later, when the service
discovery is finished, the UUIDs property is re-sent and both may
contain the HFP AG UUID.

Valgrind log:

ofonod[8157]: src/modem.c:ofono_modem_create() name: hfp/org/bluez/hci0/dev_40_98_4E_32_D7_39, type: hfp
ofonod[8157]: src/modem.c:set_modem_property() modem 0x66a2db0 property Remote
ofonod[8157]: src/modem.c:set_modem_property() modem 0x66a2db0 property DevicePath
ofonod[8157]: src/modem.c:ofono_modem_register() 0x66a2db0
ofonod[8157]: plugins/hfp_hf_bluez5.c:hfp_probe() modem: 0x66a2db0
ofonod[8157]: Modem register failed on path /hfp/org/bluez/hci0/dev_40_98_4E_32_D7_39
ofonod[8157]: plugins/hfp_hf_bluez5.c:hfp_remove() modem: 0x66a2db0
ofonod[8157]: plugins/hfp_hf_bluez5.c:profile_new_connection() Profile handler NewConnection
ofonod[8157]: src/modem.c:get_modem_property() modem 0x66a2db0 property DevicePath
==8157== Invalid write of size 4
==8157==    at 0x4712A5: hfp_slc_info_init (slc.c:59)
==8157==    by 0x486B00: profile_new_connection (hfp_hf_bluez5.c:168)
==8157==    by 0x412C70: process_message.isra.4 (object.c:258)
==8157==    by 0x5381984: _dbus_object_tree_dispatch_and_unlock (in /usr/lib64/libdbus-1.so.3.7.2)
==8157==    by 0x5373C4F: dbus_connection_dispatch (in /usr/lib64/libdbus-1.so.3.7.2)
==8157==    by 0x4107B7: message_dispatch (mainloop.c:76)
==8157==    by 0x5089BCA: g_timeout_dispatch (in /usr/lib64/libglib-2.0.so.0.3400.2)
==8157==    by 0x5089044: g_main_context_dispatch (in /usr/lib64/libglib-2.0.so.0.3400.2)
==8157==    by 0x5089377: g_main_context_iterate.isra.24 (in /usr/lib64/libglib-2.0.so.0.3400.2)
==8157==    by 0x5089771: g_main_loop_run (in /usr/lib64/libglib-2.0.so.0.3400.2)
==8157==    by 0x41042B: main (main.c:249)
==8157==  Address 0x8 is not stack'd, malloc'd or (recently) free'd
==8157==
bluez5: Unify bt_register_profile_* into a single function

It was a cause of confusion for little gain to have separate
functions for registering profiles with extra information, for
example "role" and "features". We remove that helper functions
in favor of a single one with more parameters, "role" and
"feature" when NULL will be ignored.
hfp: Add defines for HFP SDP feature bits
hfp_hf_bluez5: Register the SDP record with correct features
handsfree-audio: Fix replying to an empty D-Bus message

In the case that ofono_handsfree_card_connect_sco() is called outside the
context of a .Connect() call, there's no message we need to reply.  This
happens, for example, when the HFP AG plugin initiates a SCO connection when
it receives an AT+BCC command from the HF.
bluetooth: Add define for SCO voice settings

Add defines for SCO voice setting (Air Coding). Air mode "Transparent
Data" shall be supported if wide band speech is supported.
handsfree-audio: Add setting SCO air mode
hfp_hf_bluez5: Handle org.bluez.Profile1.Cancel()

Cancel() will be called when the ConnectProfile() is called, perhaps
even replied with a success, and the user cancels the connection
attempt.
hfp_hf_bluez5: Handle org.bluez.Profile1.Release()

There's nothing we can do in this case, so we only reply with a
success.
test: Create simple-handsfree-audio-agent

This python tool implements the org.ofono.HandsfreeAudioAgent interface,
dealing with the SCO file descriptor passed by the Handsfree Audio
Manager.
include: Add ofono_emulator_create_card()
emulator: Add Handsfree Audio Card to emulator
emulator: Register card when establish SLC
hfp_ag_bluez5: Create card for emulator when connect
emulator: Set local and remote address of card
hfp_ag_bluez5: Pass fd to card creation

We can extract local and remote address from the file descriptor.
emulator: Add init and cleanup functions
main: Call emulator init and cleanup functions
emulator: Add a Card driver for HFP 1.6

This is just the skeleton of a Handsfree Audio Card for the AG side of
HFP 1.6.
emulator: Set card driver

If the version is 1.6, passes the corresponding card driver name. If
not, passes NULL.