Fix rand-sgx tag

Author: dingelish

sgx/gbdt-sgx/Cargo.toml

@@ -26,7 +26,7 @@ crate-type = ["rlib", "staticlib"]
 serde = { git = "https://github.com/mesalock-linux/serde-sgx.git" }
 serde_derive = { git = "https://github.com/mesalock-linux/serde-sgx.git" }
 serde_json = { git = "https://github.com/mesalock-linux/serde-json-sgx.git" }
-rand={ version = "0.6", optional = true, git = "https://github.com/mesalock-linux/rand-sgx.git" }
+rand={ version = "0.6", optional = true, git = "https://github.com/mesalock-linux/rand-sgx.git", tag = "v0.6.5_sgx1.0.8" }
 regex = { version = "1", git = "https://github.com/mesalock-linux/regex-sgx", optional = true }
 time = { version = "0.1", optional = true }
 sgx_tstd = { rev = "v1.0.8", git = "https://github.com/baidu/rust-sgx-sdk.git", optional = true }