Fix some VMS inconsistencies

- The install top is versioned by default.  However, only the major
  version should be used.
- the default areas for certs, private keys an config files have
  changed, now all prefixed with 'OSSL$'.  This gets reflected in
  cryptlib.h.
- [.VMS]openssl_startup.com.in had some faults regarding creating
  rooted concealed logical names.

Reviewed-by: Rich Salz <rsalz@openssl.org>