pv: return error if shm is not initialized when $shv() is used

(cherry picked from commit bf6cb8e2dfedb5b8c6cc367ff6e8355a8313d887)
(cherry picked from commit 47b428cefd78e094c3ed4f86591072577236e5b3)

modules/pv/pv_shv.c

@@ -628,7 +628,7 @@ int param_set_xvar( modparam_t type, void* val, int mode)
 	if(!shm_initialized()!=0)
 	{
 		LM_ERR("shm not initialized - cannot set value for PVs\n");
-		goto error;
+		return -1;
 	}
 
 	s.s = (char*)val;