VMS: make sure there's a file extension when creating files

When creating the library $lib.olb, make sure the extension is there.
Otherwise, a logical name with the same name as the file in question
will redirect the creation elsewhere.
Reviewed-by: NTim Hudson <tjh@openssl.org>

Configurations/descrip.mms.tmpl

@@ -681,7 +681,7 @@ EOF
                                     @{$args{objs}}));
       return <<"EOF";
 $lib.OLB : $objs
-        LIBRARY/CREATE/OBJECT $lib
+        LIBRARY/CREATE/OBJECT $lib.OLB
         $fill_lib
         - PURGE $lib.OLB
 EOF