install: Use GError in launch_and_wait_network_handler()
install: Use GError in launch_and_wait_network_handler()

This both will provide more useful error outputs when working with the
network installation method and is a further step for making the bundle
and network install method more similar.

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

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