Fix test/recipes/80-test_ca.t to work on VMS

VMS uses a variant of openssl.cnf named openssl-vms.cnf.

There's a Perl on VMS mystery where a open pipe will not SIGPIPE when
the child process exits, which means that a loop sending "y\n" to it
will never stop.  Adding a counter helps fix this (set to 10, we know
that none of the CA.pl commands will require more).

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