[CIFS] Support for mounting to older, pre-CIFS servers added. This

allows specifying an RFC1001 target "called" name (netbios name of the
server, which can now be pecified as mount option "servernetbiosname"
but will eventually be passed in automatically on retry of host down
error messages caused when server refuses to handle default server
name and can not handle port 445). This is an important step, but
additional testing and fixup is needed to add remaining function needed
for these.

Signed-off-by: Steve French <(sfrench@us.ibm.com)>