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>
diff --git a/e_os.h b/e_os.h
index 4951335..eafa862 100644
--- a/e_os.h
+++ b/e_os.h
@@ -325,6 +325,8 @@
 #   define NO_SYS_PARAM_H
 #   define NO_SYS_UN_H
 
+#   define DEFAULT_HOME "SYS$LOGIN:"
+
 #  else
      /* !defined VMS */
 #   ifdef OPENSSL_UNISTD