Remove third_party/golang.org/x/mobile as it is no longer used with Go 1.5.

third_party/go/src/golang.org/x/mobile/example/libhello/README

-The libhello app demonstrates calling Go code from a primarily Java app.
-
-Starting in Java lets you program against Android's extensive UI
-libraries in their native language and call into Go for library code
-(business logic, code shared with a Go server, portable code).
-
-The Java entry point to the program is the file
-src/com/example/hello/MainActivity.java, where the statement
-
-        Hi.Hello("world");
-
-is a call into Go code.
-
-The Go code is in a package called hi, the file is hi/hi.go, and it
-contains the function Hello:
-
-        func Hello(name string) {
-                fmt.Printf("Hello, %s!\n", name)
-        }
-
-Java language bindings are generated for this package using the gobind
-tool. There is a user guide for gobind at 
-
-        http://golang.org/x/mobile/cmd/gobind
-
-The generated source has been included in the distribution. If you
-modify the exported interface of package hi, you have to run gobind
-manually before calling all.bash.
-
-Along with the gobind generated source, the app includes a main.go file
-to define the app entry point.
-
-make.bash builds the app, all.bash deploys it.
-
-The first step in building the app is to build the native shared
-library out of the Go code, and place it in
-libs/armeabi-v7a/libgojni.so.
-
-The second step is building the app with the standard Android build
-system by calling ant debug (also done in make.bash). Two extra Java
-files are included in the build by make.bash to support the language
-bindings. This produces an apk ready for running on a device.