tests/multipath.partition: create /var/lib/containers before mount
Otherwise, `/var/lib/containers` may not exist yet and the mount will
fail. It's usually created via tmpfiles, but we run earlier than that.
Fixes part of:
@@ -67,6 +67,8 @@ systemd:
[Service]
Type=oneshot
ExecStart=/usr/sbin/mkfs.xfs -L containers -m reflink=1 /dev/mapper/mpatha
+ # This is usually created by tmpfiles.d, but we run earlier than that.
+ ExecStart=/usr/bin/mkdir -p /var/lib/containers
[Install]
WantedBy=multi-user.target
