oeqa/runtime/systemd: skip unit enable/disable on read-only-rootfs
This doesn't work on read-only-rootfs:
AssertionError: 1 != 0 : SYSTEMD_BUS_TIMEOUT=240s systemctl disable avahi-daemon.service
Failed to disable unit: File /etc/systemd/system/multi-user.target.wants/avahi-daemon.service: Read-only file system
This patch does two things:
1) Decorate the existing test to be skipped if the rootfs is
read-only
2) add a new test to be executed only if the rootfs is
read-only. This new test remounts the rootfs read-write
before continuing to execute the existing test, making
sure to clean up correctly after itself (remount r/o
again).
Signed-off-by: André Draszik <git@andred.net> Signed-off-by: Richard Purdie <richard.purdie@linuxfoundation.org>
