Change default directory for the .rnd file on Windows and VMS

The previous change for Windows wasn't quite right.  Corrected to use
%HOME%, %USERPROFILE% and %SYSTEMPROFILE%, in that order.

Also adding the default home for VMS, SYS$LOGIN:

Reviewed-by: Matt Caswell <matt@openssl.org>
Reviewed-by: Andy Polyakov <appro@openssl.org>