netmount: fix mounting on Linux
netmount: fix mounting on Linux

Before this commit, on Linux, we were always trying to mount file
systems marked with _netdev, even when the previous mount command
failed. Now, we do not run the second mount if the first fails.

X-Gentoo-Bug: 579876
X-Gentoo-Bug-URL: https://bugs.gentoo.org/show_bug.cgi?id=579876

dwfreed/openrc,williamh/openrc,dwfreed/openrc,williamh/openrc,OpenRC/openrc,williamh/openrc,OpenRC/openrc,dwfreed/openrc,OpenRC/openrc