[CIFS] Add write perm for usr to file on windows should remove r/o dos attr

Remove read only dos attribute on chmod when adding any write permission (ie on any of
user/group/other (not all of user/group/other ie  0222) when
mounted to windows.

Suggested by: Urs Fleisch

Signed-off-by: Urs Fleisch <urs.fleisch@gmail.com>
Signed-off-by: Steve French <sfrench@us.ibm.com>