Fix re_expression matching with subdomains
    
    This patch fixes an issue which resulted in a need to initialize
    responder with data from local domain, otherwise it would not correctly
    detect requests for subdomains. Similar situation can occur if new
    subdomain is added at runtime.
    
    The solution is to ask for a list of subdomains in case there is a
    candidate domain identified in the process of matching re_expressions
    with given name.