mod_netconf: own config as source in copy-config

Allow to specify own configuration data as a source for the copy-config
operation.
diff --git a/src/test-client.c b/src/test-client.c
index a701da1..1664bdc 100644
--- a/src/test-client.c
+++ b/src/test-client.c
@@ -157,7 +157,14 @@
 		printf("Source (running|startup|candidate): ");
 		getline (&line, &len, stdin);
 		line[(strlen(line)-1)] = 0;
-		json_object_object_add(msg, "source", json_object_new_string(line));
+		if (strlen(line) > 0) {
+			json_object_object_add(msg, "source", json_object_new_string(line));
+		} else {
+			printf("Configuration data: ");
+			getline (&line, &len, stdin);
+			line[(strlen(line)-1)] = 0;
+			json_object_object_add(msg, "config", json_object_new_string(line));
+		}
 		printf("Target (running|startup|candidate): ");
 		getline (&line, &len, stdin);
 		line[(strlen(line)-1)] = 0;