Core Update 167: Replace /etc/mtab by symlink to /proc/self/mounts

mount, as updated via util-linux, no longer writes /etc/mtab, causing
programs to rely on this file's content (such as the check_disk Nagios
plugin) to stop working.

/proc/self/mounts contains all the necessary information, so it is fine
to replace /etc/mtab by a symlink to it.

Fixes: #12843

Signed-off-by: Peter Müller <peter.mueller@ipfire.org>

src/initscripts/system/mountfs

@@ -31,12 +31,6 @@ case "${1}" in
 		# Remove fsck-related file system watermarks.
 		rm -f /fastboot /forcefsck
 
-		boot_mesg "Create /etc/mtab..."
-		> /etc/mtab
-		mount -f / || failed=1
-		(exit ${failed})
-		evaluate_retval
-
 		# This will mount all filesystems that do not have _netdev in
 		# their option list.  _netdev denotes a network filesystem.
 		boot_mesg "Mounting remaining file systems..."

src/initscripts/system/partresize

@@ -30,12 +30,6 @@ case "${1}" in
 			mount -o remount,rw / > /dev/null
 			evaluate_retval
 
-			boot_mesg "Create /etc/mtab..."
-			> /etc/mtab
-			mount -f / || failed=1
-			(exit ${failed})
-			evaluate_retval
-
 			# check if serial console enabled
 			scon="off";
 			if [ ! "$(grep "console=ttyS0" /proc/cmdline)" == "" ]; then