fsogsmd: pdp_qmi plugin: check if registered

[Lukas-David Gorris]

Trying to get a data connection up on htcleo machine, I failed because I
didn't realize one has to wait until the radio is registered to network.

I tested this using the SHR distribution. Settings/Connectivity menu offers a
GUI to connect to 'GPRS'. In case of htcleo and other htc machines I
think this should be handled by fsogsmd/src/plugins/pdp_qmi/plugin.vala

Turns out this lacks any check for network register state. Despite the
user not understanding why the connection is failing (no errors: it will
just say connecting... connected.) this is particularly bad for the
following reason:

Once one attempts to connect in unregistered state, the device has to be
rebooted in order to connect.

We should add a condition that will check for
"FreeSmartphone.GSM.DeviceStatus.ALIVE_REGISTERED" and if false, end the
process with an according error message.

Additionally a mechanism to check if the connection is truly up would  
be good. Dmesg might be used: it will throw some qmi0: connection  
failed error if it doesn't work.


Best,

Lukas