--link-dest non-optimal without --owner (or when not root)

[Stephen Gildea]

If I run rsync 2.5.6 not as root, so that the -o (--owner) and 
-g (--group) flags don't work, then files that are not owned by me in
the source directory will not be linked by --link-dest.

When rsync looks in my link-dest, it sees a file owned by me.  When it
compares that with the source file not owned by me, then rsync thinks it
cannot skip that file, and no hard link results.  However, because I am
not running rsync as root, the resulting new file is owned by me, same
as the rejected link-dest file.

The result is that I have two copies of the file, one in the link-dest
directory and the other in the destination directory, that are
identical, that should be linked, but that are not linked.

Perhaps the "skip file" algorithm in rsync should compare the
destination file with the user/group that the source file would become,
not with what it is.

 < Stephen