filefrag: exit with error code if an error is hit

filefrag: exit with error code if an error is hit

If an error is hit during filefrag operation, it will continue to run
(if multiple files are specified on the command-line), but will exit
with a non-zero value, so that callers can determine that some error
was hit.

Clean up the printing of FIEMAP flags and print some newer flags that
were missing.  Also print unknown flags as hex values.

Signed-off-by: Andreas Dilger <adilger@dilger.ca>
Signed-off-by: Theodore Ts'o <tytso@mit.edu>