src/main: strip remote error information from D-Bus errors
src/main: strip remote error information from D-Bus errors

This strips unnecessary information as:

| GDBus.Error:org.gtk.GDBus.UnmappedGError.Quark._g_2dio_2derror_2dquark.Code30:

to make the remote error more readable.

Signed-off-by: Enrico Jorns <a2e5f936c390f36494e46e71bcfbe365bb1e8c49@pengutronix.de>

rauc/rauc,rauc/rauc,rauc/rauc,jluebbe/rauc,ejoerns/rauc,ejoerns/rauc,ejoerns/rauc,jluebbe/rauc,jluebbe/rauc