LU-540 quota: add compatibility for 1.8 userspace

LU-540 quota: add compatibility for 1.8 userspace

The LL_IOC_QUOTACTL ioctl data structure if_quotactl changed size
in 2.x by adding new fields in the middle of the structure.  Add
compatibility for the old 1.8 quotactl userspace ioctl so that it
is possible for existing quotactl tools to run on both 1.x and 2.x.

This requires renumbering the LL_IOC_QUOTACTL ioctl, since it had
incorrectly used "struct if_quotactl *" as the "size" parameter,
but the _pointer_ size did not change.  ioctl() values should always
take a struct as the size parameter, not a pointer to the struct,
so that issues like this can be caught earlier.

Change-Id: I0bce98327a276c0c9a49ce78efd3f45e00df7168
Signed-off-by: Andreas Dilger <adilger@whamcloud.com>
Reviewed-on: http://review.whamcloud.com/1152
Tested-by: Hudson
Reviewed-by: Fan Yong <yong.fan@whamcloud.com>
Tested-by: Maloo <whamcloud.maloo@gmail.com>
Reviewed-by: Oleg Drokin <green@whamcloud.com>