orangefs: never trust cache, always call pvfs2_d_revalidate_common.

Signed-off-by: Mike Marshall <hubcap@omnibond.com>
orangefs: fix extended attr problem...

Two problems, actually.

reserved key detection code had gotten logic crossed up...

length-of-xattr as returned by orangefs includes the null at the
end of a string, which confuses string functions.

Tested the length fix with these edge conditions...
setfattr -n "user.two" -v "12" /pvfsmnt/two
setfattr -n "user.one" -v "1" /pvfsmnt/one
setfattr -n "user.zero" -v "" /pvfsmnt/zero

Signed-off-by: Mike Marshall <hubcap@omnibond.com>