ims_dialog: declare extern dlg stats structure in header file

src/modules/ims_dialog/dlg_ng_stats.c

@@ -1,6 +1,6 @@
 #include "dlg_ng_stats.h"
 
-struct dialog_ng_counters_h dialog_ng_cnts_h;
+struct dialog_ng_counters_h dialog_ng_cnts_h = {0};
 
 /* dialog_ng counters definitions */
 counter_def_t dialog_ng_cnt_defs[] =  {
@@ -31,4 +31,4 @@ error:
 void dialog_ng_stats_destroy()
 {
 	/* do nothing */
-}
+}

src/modules/ims_dialog/dlg_ng_stats.h

@@ -11,9 +11,9 @@ struct dialog_ng_counters_h {
 
 };
 
-struct dialog_ng_counters_h dialog_ng_cnts_h;
+extern struct dialog_ng_counters_h dialog_ng_cnts_h;
 
 int dialog_ng_stats_init();
 void dialog_ng_stats_destroy();
 
-#endif	/* DIALOG_NG_STATS_H */
+#endif	/* DIALOG_NG_STATS_H */