filefrag: fix issues with 29758d2

filefrag: fix issues with 29758d2

29758d2 filefrag: exit with error code if an error is hit

introduced a couple errors; in one case it missed returning
a value, and possibly picked up errno from (unchecked) close(),
and in the other used a test where it needed an
assignment.  So capture the error, move perror() directly
after the failed call in both cases, and fix the assignment.

Also fix a precedence problem with:

	if (fe_flags & mask == 0)

which is equivalent to:

	if (fe_flags & (mask == 0))

but we need:

	if ((fe_flags & mask) == 0)

Signed-off-by: Eric Sandeen <sandeen@redhat.com>
Signed-off-by: Theodore Ts'o <tytso@mit.edu>
Reviewed-by: Andreas Dilger <adilger@dilger.ca>