Fix some test deps

 * Cert revocation tests require `MBEDTLS_HAVE_TIME_DATE`.
 * Verison features tests require... well, `MBEDTLS_VERSION_FEATURES`, actually.

Fixes https://github.com/ARMmbed/mbedtls/issues/1475
diff --git a/tests/suites/test_suite_version.function b/tests/suites/test_suite_version.function
index 37144ca..a4847f9 100644
--- a/tests/suites/test_suite_version.function
+++ b/tests/suites/test_suite_version.function
@@ -64,7 +64,7 @@
 }
 /* END_CASE */
 
-/* BEGIN_CASE */
+/* BEGIN_CASE depends_on:MBEDTLS_VERSION_FEATURES */
 void check_feature( char *feature, int result )
 {
     int check = mbedtls_version_check_feature( feature );