bump log version

Author: hgzimmerman

Cargo.toml

@@ -21,7 +21,7 @@ hyper = "^0.10"
 serde = "^1.0"
 serde_json = "^1.0"
 serde_derive = "^1.0"
-log = "^0.3"
+log = "^0.4"
 rand = "^0.3"
 rustyline = { version = "^1.0", optional = true }
 stderrlog = "^0.2"