remove unused `failure' dep from Cargo.toml

Author: Eric S. Londres

Cargo.toml

@@ -13,7 +13,6 @@ chrono = "0.4"
 daemonize = "0.4"
 dbus = { version = "0.6", optional = true }
 dbus-tokio = { version = "0.2", optional = true }
-failure = "0.1.7"
 fern = { version = "0.6.0", features = ["syslog-4"] }
 futures = "0.1"
 gethostname = "0.2.0"