Fix bug 2999830: do not report failed chown() on copy.

Fix bug 2999830: do not report failed chown() on copy.

Debian bug 574853 reported by Ian Zimmerman <itz@buug.org>

I was trying to copy images from my camera which is mounted as a USB
mass storage device.  The files on the mount are owned by root, and
geeqie tries to chown (and chgrp) the copy, fails, and displays an
error message.  This is only mildly annoying when copying a single
file, but when I want to copy multiple files the failure stops the
operation after the first file.

Patch by Vladislav Naumov <vnaum@vnaum.com>

This patch ignores chown errors, while still doing chown
(so root still can copy files preserving ownership).

http://sourceforge.net/tracker/?func=detail&aid=2999830&group_id=222125&atid=1054680
http://bugs.debian.org/cgi-bin/bugreport.cgi?bug=574853 (original report)