test/install: add incremental test case for do_install_network
test/install: add incremental test case for do_install_network

Signed-off-by: Jan Luebbe <9f5a27cdf1a1d6dd5e7372203be5c3a13524cbc8@debian.org>

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