Support for checking file systems from /etc/fstab

This patch adds support for running fsck on all file systems listed in
/etc/fstab with a passno > 0.  The fsck runs sequentially, starting with
the root fs (passno 1).

Signed-off-by: Joachim Nilsson <troglobit@gmail.com>

contrib/alpine/finit.conf

@@ -6,9 +6,6 @@
 module button
 module evdev
 
-# Devices to fsck at boot
-check /dev/vda1
-
 # Runlevel to start after bootstrap, runlevel 'S'
 runlevel 2