json: Support older jansson versions.

The use of '?' is a fairly new addition to jansson and is not
supported in the version of jansson that can be used by 13.
This change returns to previous supported behavior and removes
usage of '?'.

ASTERISK-28663

Change-Id: I6d596007ae85e8724d928865d99968f679be1142

main/json.c

@@ -895,12 +895,12 @@ struct ast_json *ast_json_name_number(const char *name, const char *number)
 struct ast_json *ast_json_dialplan_cep_app(
 		const char *context, const char *exten, int priority, const char *app_name, const char *app_data)
 {
-	return ast_json_pack("{s: s?, s: s?, s: o, s: s?, s: s?}",
-		"context", context,
-		"exten", exten,
+	return ast_json_pack("{s: o, s: o, s: o, s: o, s: o}",
+		"context", context ? ast_json_string_create(context) : ast_json_null(),
+		"exten", exten ? ast_json_string_create(exten) : ast_json_null(),
 		"priority", priority != -1 ? ast_json_integer_create(priority) : ast_json_null(),
-		"app_name", app_name,
-		"app_data", app_data
+		"app_name", app_name ? ast_json_string_create(app_name) : ast_json_null(),
+		"app_data", app_data ? ast_json_string_create(app_data) : ast_json_null()
 		);
 }
 

res/res_stasis_playback.c

@@ -105,7 +105,7 @@ static struct ast_json *playback_to_json(struct stasis_message *message,
 		return NULL;
 	}
 
-	return ast_json_pack("{s: s, s: o?, s: O}",
+	return ast_json_pack("{s: s, s: o, s: O}",
 		"type", type,
 		"timestamp", ast_json_timeval(*stasis_message_timestamp(message), NULL),
 		"playback", blob);

res/res_stasis_recording.c

@@ -91,7 +91,7 @@ static struct ast_json *recording_to_json(struct stasis_message *message,
 		return NULL;
 	}
 
-	return ast_json_pack("{s: s, s: o?, s: O}",
+	return ast_json_pack("{s: s, s: o, s: O}",
 		"type", type,
 		"timestamp", ast_json_timeval(*stasis_message_timestamp(message), NULL),
 		"recording", blob);

res/stasis/app.c

@@ -1164,7 +1164,7 @@ void app_update(struct stasis_app *app, stasis_app_cb handler, void *data)
 
 		ast_verb(1, "Replacing Stasis app '%s'\n", app->name);
 
-		msg = ast_json_pack("{s: s, s: o?, s: s}",
+		msg = ast_json_pack("{s: s, s: o, s: s}",
 			"type", "ApplicationReplaced",
 			"timestamp", ast_json_timeval(ast_tvnow(), NULL),
 			"application", app->name);