Upgrade libbindgen to 0.1.5

0.1.4 is known for being broken on Windows, and earlier version may not work properly in various platforms.
servo · bors-servo · Dec 29, 2016 · Dec 29, 2016 · Dec 29, 2016 · f1f1466aa19b037de0004e4f293aa3c71ee8e58c
commit f1f1466aa19b037de0004e4f293aa3c71ee8e58c
diff --git a/Cargo.lock b/Cargo.lock
diff --git a/components/style/Cargo.toml b/components/style/Cargo.toml
@@ -66,7 +66,7 @@ kernel32-sys = "0.2"
 
 [build-dependencies]
 lazy_static = "0.2"
-libbindgen = {version = "0.1.1", optional = true}
+libbindgen = {version = "0.1.5", optional = true}
 phf_codegen = "0.7.20"
 regex = {version = "0.1", optional = true}
 walkdir = "0.1"