cp: Don't warn for chflags() failing with EOPNOTSUPP if flags == 0

[imp]

Summary

From NetBSD's utils.c 1.5 importing importing BSDI change, with light
formatting changes:

Author: cgd <[e-mail]>
Date:   Wed Feb 26 14:40:51 1997 +0000

Patch from BSDI (via Keith Bostic):
>NFS doesn't support chflags; ignore errors unless there's reason
>to believe we're losing bits.  (Note, this still won't be right
>if the server supports flags and we were trying to *remove* flags
>on a file that we copied, i.e., that we didn't create.)

CVS Info: utils.c 1.6

Obtained from: NetBSD
Sponsored by: Netflix