Add ZFS dependencies to the initrd so that the zpool command works.

Remove unneeded zfs mount, since zpool automatically mounts everything.

Close #1128.

nixos/modules/tasks/filesystems/zfs.nix

@@ -55,11 +55,12 @@ in
           cp -v ${kernel.zfs}/sbin/zfs $out/bin
           cp -v ${kernel.zfs}/sbin/zdb $out/bin
           cp -v ${kernel.zfs}/sbin/zpool $out/bin
+          cp -pdv ${kernel.zfs}/lib/lib*.so* $out/lib
+          cp -pdv ${pkgs.zlib}/lib/lib*.so* $out/lib
         '';
       postDeviceCommands =
         ''
           zpool import -f -a -d /dev
-          zfs mount -a
         '';
     };