http_async_client: remove double #include<>d headers

src/modules/http_async_client/http_async_client_mod.c

@@ -47,7 +47,6 @@
 #include "../../core/pvar.h"
 #include "../../core/mem/shm_mem.h"
 #include "../../core/mod_fix.h"
-#include "../../core/pvar.h"
 #include "../../core/cfg/cfg_struct.h"
 #include "../../core/fmsg.h"
 #include "../../core/kemi.h"