pnfsmanager: update atime on get attribute if desired

PnfsManager still controls the time interval during which updates are ignored.

Acked-by: Gerd Behrmann
Target: master
Require-book: yes
Require-notes: yes
chimera: make Stat aware of defined attributes

update FsSqlDriver to generate SQL statement for required
attributes only.

Acked-by: Gerd Behrmann
Target: master
Require-book: no
Require-notes: no
chimera-provider: do not get file attributes prior update

Acked-by: Gerd Behrmann
Target: master
Require-book: no
Require-notes: yes