[connman] fix NULL pointer crash connman_device_set_disconnected
(device=0x0, disconnected=<optimized out>) at src/device.c:765
[connman] fix NULL pointer crash g_dhcp_client_start (dhcp_client=0x0,
last_address=0xdb5e8 "10.0.1.125") at gdhcp/client.c:2666
[connman] fix null pointer crash #3  0x000447e0 in
allow_property_changed (service=0x174950) at src/service.c:4722
Merge pull request #66 from lpotter/master

[connman] fix NULL pointer crashes