config: Get rid of the dynamic seen array

* This makes the array constant in the session structure, avoiding
   allocations and frees while parsing the file
 * It also drops passing the seen array to all the functions,
   because it is already part of the passed session
 * The test cases are adjusted to match these changes

Signed-off-by: Jakub Jelen <jjelen@redhat.com>
Reviewed-by: Andreas Schneider <asn@cryptomilk.org>

tests/torture.h

@@ -120,6 +120,8 @@ void torture_setup_sshd_server(void **state);
 void torture_teardown_socket_dir(void **state);
 void torture_teardown_sshd_server(void **state);
 
+void torture_reset_config(ssh_session session);
+
 /*
  * This function must be defined in every unit test file.
  */