misc: fix missing variable names in function prototype

misc: fix missing variable names in function prototype

If libarchive support is not available or has been disable, the
function __populate_fs_from_tar() just prints an error message, and
doesn't use any of the function paramaters.  Newer versions of gcc
won't complain about the missing function names, since newer C
standards allow this, but it breaks on older versions of gcc.

Also return the error code ENOTSUP instead of 1.

https://github.com/tytso/e2fsprogs/issues/213

Signed-off-by: Theodore Ts'o <tytso@mit.edu>