ocfs2: Move OLQF_CLEAN flag out of generic quota flags

OLQF_CLEAN flag is used by OCFS2 on disk to recognize whether quota
recovery is needed or not. We also somewhat abuse mem_dqinfo->dqi_flags
to pass this flag around. Use private flags for this to avoid clashes
with other quota flags / not pollute generic quota flag namespace.

Signed-off-by: Jan Kara <jack@suse.cz>