Do not overload mount-call - trying to reduce confusion

Do not overload mount-call - trying to reduce confusion

The behaviour of calling 'mount' differed depending on whether it called
the busybox-mount, the mount of util-linux, the mount defined in
/lib/functions.sh and /lib/functions/boot.sh

/etc/preinit even included /lib/functions.sh and /lib/functions/boot.sh,
both re-defining 'mount'.

git-svn-id: svn://svn.openwrt.org/openwrt/trunk@34792 3c298f89-4303-0410-b956-a3cf2f4a3e73