use patch feature for failure master RC testing

github: rust-lang-deprecated/failure#230 rust-lang-deprecated/failure@3d5b8f91

Cargo.toml

@@ -29,7 +29,7 @@ travis-ci = { repository = "dekellum/body-image" }
 brotli     = { version = ">=2.2.1, <3", optional = true }
 bytes      = ">=0.4.6, <2"
 clap       = { version = ">=2.31.2, <3", optional = true, default-features = false, features = ["wrap_help"] }
-failure = { git = "https://github.com/rust-lang-nursery/failure", branch = "master" }
+failure    = ">=0.1.0, <2"
 fern       = { version = ">=0.5.5, <2", optional = true }
 flate2     = ">=1.0.1, <2"
 futures    = { version = ">=0.1.20, <0.2", optional = true }
@@ -74,4 +74,7 @@ features = ["mmap", "brotli", "async"]
 lazy_static = { version = ">=1.0.1, <2" }
 fern        = { version = ">=0.5.5, <2" }
 hyper-stub  = { version = ">=0.1.0, <2" }
-rand        = { version = ">=0.4.2, <2" }
+rand        = { version = ">=0.4.2, <2" }
+
+[patch.crates-io]
+failure = { git = "https://github.com/rust-lang-nursery/failure", branch = "master" }