Automatic merge from submit-queue (batch tested with PRs 38294, 37009, 36778, 38130, 37835)

fix permissions when using fsGroup

Currently, when an fsGroup is specified, the permissions of the defaultMode are not respected and all files created by the atomic writer have mode 777.  This is because in `SetVolumeOwnership()` the `filepath.Walk` includes the symlinks created by the atomic writer.  The symlinks have mode 777 when read from `info.Mode()`.  However, when the are chmod'ed later, the chmod applies to the file the symlink points to, not the symlink itself, resulting in the wrong mode for the underlying file.

This PR skips chmod/chown for symlinks in the walk since those operations are carried out on the underlying file which will be included elsewhere in the walk.

xref https://bugzilla.redhat.com/show_bug.cgi?id=1384458

@derekwaynecarr @pmorie