host: Don't try to resolve %any* keywords with mismatched address family

While host_create_from_string_and_family() usually replaces %any*
keywords, this fails if the address family doesn't match (e.g. %any4 with
AF_INET6).  There is no point in trying to resolve these keywords via
DNS as % is no valid character for host names.

Closes strongswan/strongswan#2880

src/libstrongswan/networking/host.c

@@ -461,7 +461,7 @@ host_t *host_create_from_dns(char *string, int af, uint16_t port)
 	host_t *this;
 
 	this = host_create_from_string_and_family(string, af, port);
-	if (!this)
+	if (!this && string && string[0] != '%')
 	{
 		this = lib->hosts->resolve(lib->hosts, string, af);
 	}