readme: fix git command

License: MIT
Signed-off-by: Steven Allen <steven@stebalien.com>

README.md

@@ -132,7 +132,7 @@ export PATH=$PATH:$GOPATH/bin
 #### Download and Compile IPFS
 
 ```
-$ git https://github.com/ipfs/go-ipfs.git
+$ git clone https://github.com/ipfs/go-ipfs.git
 
 $ cd go-ipfs
 $ make install