Update syntex for the latest changes and bump version to 0.5.4.

Cargo.toml

@@ -9,26 +9,26 @@ license = "MIT"
 name = "etcd"
 readme = "README.md"
 repository = "https://github.com/jimmycuadra/rust-etcd"
-version = "0.5.3"
+version = "0.5.4"
 
 [build-dependencies.serde_codegen]
 optional = true
-version = "0.7.2"
+version = "0.7.7"
 
 [build-dependencies.syntex]
 optional = true
-version = "0.31.0"
+version = "0.33.0"
 
 [dependencies]
 hyper = "0.8.1"
-openssl = "0.7.9"
-serde = "0.7.0"
-serde_json = "0.7.0"
+openssl = "0.7.13"
+serde = "0.7.7"
+serde_json = "0.7.1"
 url = "0.5.9"
 
 [dependencies.serde_macros]
 optional = true
-version = "0.7.2"
+version = "0.7.7"
 
 [features]
 default = ["serde_codegen", "syntex"]