Some config parsing fixes

src/messenger.cpp

@@ -525,7 +525,8 @@ json11::Json osd_messenger_t::read_config(const json11::Json & config)
     int fd = open(config_path, O_RDONLY);
     if (fd < 0)
     {
-        fprintf(stderr, "Error reading %s: %s\n", config_path, strerror(errno));
+        if (errno != ENOENT)
+            fprintf(stderr, "Error reading %s: %s\n", config_path, strerror(errno));
         return config;
     }
     struct stat st;

src/osd.cpp

@@ -112,6 +112,8 @@ void osd_t::parse_config(const json11::Json & config)
         immediate_commit = IMMEDIATE_ALL;
     else if (config["immediate_commit"] == "small")
         immediate_commit = IMMEDIATE_SMALL;
+    else
+        immediate_commit = IMMEDIATE_NONE;
     if (!config["autosync_interval"].is_null())
     {
         // Allow to set it to 0

src/qemu_driver.c

@@ -199,9 +199,9 @@ static int vitastor_file_open(BlockDriverState *bs, QDict *options, int flags, E
     client->etcd_host = g_strdup(qdict_get_try_str(options, "etcd_host"));
     client->etcd_prefix = g_strdup(qdict_get_try_str(options, "etcd_prefix"));
     client->rdma_device = g_strdup(qdict_get_try_str(options, "rdma_device"));
-    client->rdma_port_num = qdict_get_int(options, "rdma_port_num");
-    client->rdma_gid_index = qdict_get_int(options, "rdma_gid_index");
-    client->rdma_mtu = qdict_get_int(options, "rdma_mtu");
+    client->rdma_port_num = qdict_get_try_int(options, "rdma_port_num", 0);
+    client->rdma_gid_index = qdict_get_try_int(options, "rdma_gid_index", 0);
+    client->rdma_mtu = qdict_get_try_int(options, "rdma_mtu", 0);
     client->proxy = vitastor_proxy_create(
         bdrv_get_aio_context(bs), client->config_path, client->etcd_host, client->etcd_prefix,
         client->rdma_device, client->rdma_port_num, client->rdma_gid_index, client->rdma_mtu