Fix http_req sample on http_req 0.6
diff --git a/samplecode/http_req/enclave/Xargo.toml b/samplecode/http_req/enclave/Xargo.toml
index 26fd2ce..c7a9778 100644
--- a/samplecode/http_req/enclave/Xargo.toml
+++ b/samplecode/http_req/enclave/Xargo.toml
@@ -63,7 +63,7 @@
 
 [dependencies.std]
 path = "../../../xargo/sgx_tstd"
-features = ["net"]
+features = ["net", "untrusted_time"]
 stage = 5
 
 [dependencies.sgx_no_tstd]