maint: chown, chgrp, chmod, chcon: remove unnecessary initialization

maint: chown, chgrp, chmod, chcon: remove unnecessary initialization

* src/chown-core.c: Include "ignore-value.h".
(change_file_owner): Don't set "ent" only to ignore it.
* src/chcon.c (process_file): Likewise.
* src/chmod.c: Include "ignore-value.h".
(process_file): Don't set "ent" only to ignore it.
After diagnosing root-dev/ino failure, return false immediately:
Now that we don't set "ent" we must be sure not to use it uninitialized,
and there's no point in issuing --verbose-related output in this case.