Remember that the port was set in host and nslookup

Set 'port_set = true;' so that the TCP/DOT/DOH code doesn't reset
the port when making connections.

bin/dig/host.c

@@ -848,6 +848,7 @@ parse_args(bool is_batchfile, int argc, char **argv) {
 			break;
 		case 'p':
 			port = atoi(isc_commandline_argument);
+			port_set = true;
 			break;
 		}
 	}

bin/dig/nslookup.c

@@ -569,6 +569,7 @@ set_port(const char *value) {
 	isc_result_t result = parse_uint(&n, value, 65535, "port");
 	if (result == ISC_R_SUCCESS) {
 		port = (uint16_t)n;
+		port_set = true;
 	}
 }