tests/Makefile.am: Update for bionic

-lpthread doesn't exist and isn't necessary on bionic.

Signed-off-by: Stéphane Graber <stgraber@ubuntu.com>
Don't call setup_mount_entries if the list is empty

There's no good reason to call setup_mount_entries if we don't have any
lxc.mount.entry. This also avoids an issue on bionic where the tmpfile()
call in setup_mount_entries requires the presence of /tmp which isn't the
case by default.

Signed-off-by: Stéphane Graber <stgraber@ubuntu.com>
create rslave chroot any time pivot_root fails with -EINVAL

Note we still need the function to detect a MS_SHARED /, bc
if we detect that then we need to umount the chroot tmpfs
mount which lxc-start created, whose mount was forwarded to
the host mounts namespace.

Signed-off-by: Serge Hallyn <serge.hallyn@ubuntu.com>
Acked-by: Stéphane Graber <stgraber@ubuntu.com>
Makefile.am: Add missing liblxc symlink

Signed-off-by: Stéphane Graber <stgraber@ubuntu.com>