Fix cache_basic configuration

The test requires the old default values.

maxscale-system-test/cnf/maxscale.cnf.template.cache_basic

@@ -56,6 +56,8 @@ socket=default
 type=filter
 module=cache
 storage=storage_inmemory
+selects=verify_cacheable
+cached_data=shared
 # NOTE: If you adjust the TTL values, ensure that test programs dependent
 # NOTE: on the TTL are ajusted as well.
 hard_ttl=10