Fix GPS emulation.

Fix GPS emulation.

The problem was that qemu_gps_set_position_mode() was called with the value
GPS_POSITION_MODE_MS_BASED, which corresponds to AGPS (Assisted GPS), and
returned an error (which was not properly filtered by the JNI caller, but this
is the subject of another change).

This explains why GPS emulation doesn't work in the 1.5_r1 SDK. Unfortunately,
this fix requires generating a new system image for 1.5_r2 :-(

By the way, Mike, I don't understand why this position mode is being passed.
Looking at the code in GpsLocationProvider.java, I believe that this can only
happen if a SUPL host is given by the network, and I don't think this is the
case in the emulator, is it?