Add "json_pretty" log format, currently the same as "json".

In a future version, "json" will be an alias for "json_compact"
instead.  GitHub issue #357.

plugins/sudoers/sudoers.c

@@ -1554,3 +1554,30 @@ sudoers_get_context(void)
 {
     return &sudoers_ctx;
 }
+
+bool
+sudoers_set_log_format(enum def_tuple tuple)
+{
+    enum eventlog_format format;
+    debug_decl(cb_log_format, SUDOERS_DEBUG_PLUGIN);
+
+    switch (tuple) {
+    case json:
+        format = EVLOG_JSON;
+        break;
+    case json_compact:
+        format = EVLOG_JSON_COMPACT;
+        break;
+    case json_pretty:
+        format = EVLOG_JSON_PRETTY;
+        break;
+    case sudo:
+        format = EVLOG_SUDO;
+        break;
+    default:
+	debug_return_bool(false);
+    }
+    eventlog_set_format(format);
+
+    debug_return_bool(true);
+}