e2fsprogs: refactor to fix conflicts with busybox and util-linux

e2fsprogs: refactor to fix conflicts with busybox and util-linux

So far we attempted to solve the conflicts between busybox and e2fsprogs
by removing busybox programs from /bin and /sbin, leaving the e2fsprogs
ones at /usr/bin and /usr/sbin. This fails with BR2_ROOTFS_MERGED_USR=y,
leading to situations like the one described in bug 9436.

We could provide a better solution by means of a fine-grained selection
of programs, like util-linux does, but this would require big changes in
e2fsprogs. So instead of resorting to dirty tricks we switch to a more
pragmatic approach:

- Drop all configs to select/deselect utilities without corresponding
  enable/disable options to the configure script. In other words, we
  always install the basic set of utilities.

- fsck has a configure option, so use it. Note that --enable-fsck is
  only about the wrapper, not about e2fsck.

- Install e2fsprogs utilities at /bin and /sbin, overriding the ones
  eventually installed by busybox.

- Let the e2fsprogs build system create the symlinks mkfs.ext2 -> mke2fs
  etc.  fsck.ext4dev and mkfs.ext4dev were dropped in version 1.43.4.

Notice that these changes do exactly the opposite of what is requested
in bug 9436. On the other hand the policy for e2fsprogs becomes coherent
with the one for util-linux: busybox never wins.

Fixes:
  https://bugs.busybox.net/show_bug.cgi?id=9436 (no fix, in fact)

Signed-off-by: Carlos Santos <casantos@datacom.ind.br>
[Arnout:
 - don't add 'default y' to resize2fs;
 - don't install the host package in /bin instead of /usr/bin - we
   install everything under /usr (until /usr will be removed, soon)]
Signed-off-by: Arnout Vandecappelle (Essensium/Mind) <arnout@mind.be>
Signed-off-by: Thomas Petazzoni <thomas.petazzoni@free-electrons.com>