Provide correct instructions to build github/hub

See #1404, closes #1929 [ci skip]

README.md

@@ -72,10 +72,15 @@ in your executable path.
 
 With your [GOPATH](https://github.com/golang/go/wiki/GOPATH) already set up:
 
-``` sh
-$ go get github.com/github/hub
-$ cd "$GOPATH"/src/github.com/github/hub
-$ make install prefix=/usr/local
+```sh
+mkdir -p "$GOPATH"/src/github.com/github
+git clone \
+  --config transfer.fsckobjects=false \
+  --config receive.fsckobjects=false \
+  --config fetch.fsckobjects=false \
+  https://github.com/github/hub.git "$GOPATH"/src/github.com/github/hub
+cd "$GOPATH"/src/github.com/github/hub
+make install prefix=/usr/local
 ```
 
 Prerequisites for compilation are: