pkcs11-proxy: exit gracefully when no socket is defined

gck-rpc-module.c

@@ -1258,6 +1258,9 @@ static CK_RV rpc_C_Initialize(CK_VOID_PTR init_args)
 					 sizeof(pkcs11_socket_path),
 					 "%s.pkcs11", path);
 			pkcs11_socket_path[sizeof(pkcs11_socket_path) - 1] = 0;
+		} else {
+			ret =  CKR_FUNCTION_NOT_SUPPORTED;
+			goto done;
 		}
 	}