xfs_fsr: fix leaks & catch error in fsrfile()

xfs_fsr: fix leaks & catch error in fsrfile()

The allocated fshandlep leaks on most error paths; restructure with
an out: target that does all necessary freeing, and initialize
filehandles to -1 so that we know whether they need to be closed on
the error path.

While we're at it, if gettmpname() fails, we still return 0 for an
error, because error is initialized to 0 and only set otherwise by
fsrfile_common.  So if gettmpname() fails, we return success from
the function even though we did no work.  Fix that as well by
initializing error to -1.

Signed-off-by: Eric Sandeen <sandeen@redhat.com>
Reviewed-by: Brian Foster <bfoster@redhat.com>
Signed-off-by: Dave Chinner <david@fromorbit.com>