xtest: regression 1027: fix build warning when openssl not used

Fix build warning reported with trace message like below:

.../optee-test-custom/host/xtest/regression_1000.c:2049:20: error: ‘client_uuid_linux_ns’ defined but not used [-Werror=unused-variable]
 static const char *client_uuid_linux_ns = "58ac9ca0-2086-4683-a1b8-ec4bc08e01b6";
                    ^~~~~~~~~~~~~~~~~~~~

Fixes: 8e070bc41e1d ("xtest: disable tests 1027 and 1028 if no OpenSSL")
Signed-off-by: Etienne Carriere <etienne.carriere@linaro.org>
Acked-by: Jens Wiklander <jens.wiklander@linaro.org>
diff --git a/host/xtest/regression_1000.c b/host/xtest/regression_1000.c
index 471597d..4bb0725 100644
--- a/host/xtest/regression_1000.c
+++ b/host/xtest/regression_1000.c
@@ -2128,6 +2128,7 @@
 	TEEC_CloseSession(&session);
 #else /*!OPENSSL_FOUND*/
 	UNUSED(c);
+	UNUSED(client_uuid_linux_ns);
 	/* xtest_uuid_v5() depends on OpenSSL */
 	Do_ADBG_Log("OpenSSL not available, skipping test 1027");
 #endif