review: move global variable to .c

Signed-off-by: NLiFeng <lifeng68@huawei.com>

src/plugin/plugin.c

@@ -65,6 +65,8 @@
 #define PluginServicePostStop "/PluginService/PostStop"
 #define PluginServicePostRemove "/PluginService/PostRemove"
 
+static plugin_manager_t *g_plugin_manager;
+
 static int pm_init_plugin(const plugin_t *plugin);
 
 static int plugin_event_pre_start_handle(const plugin_t *plugin, const char *cid);

src/plugin/plugin.h

@@ -78,8 +78,6 @@ typedef struct plugin_manager {
     map_t *eps;                         /* watch_event:plugins */
 } plugin_manager_t;
 
-plugin_manager_t *g_plugin_manager;
-
 /*
  * init at isulad start, scan and init/sync all plugins
  */