[linux-cifs-client] mount flags and nosuid

[Steve French]

I was looking at problems not honoring NOSUID mount flags in cifs mounts
(except when mount.cifs is missing)and noticed I missed others as well. 
Presumably when sys mount is invoked through a utility (or even through
a mount helper) rather than solely via mount (as it is for jfs e.g.)
then the utility or mount helper must be able to parse NOSUID, NOEXEC,
NODEV (since those get copied to the vfsmount struct and are important
to filesystem neutral vfs code in fs/namespace.c), and others presumably
as well.  In mount.cifs other than the mandatory locking flag and
readonly flag I was parsing and optionally setting few of the
interesting mount flags.  

Fixing that now.