Improve clone command in README

Without the explicit dir at the end the repository will be cloned to "code".

Change-Id: Icd8b55b4ba74f23b214c3844e2fb785377768119
Signed-off-by: Freddie Chopin <freddie.chopin@gmail.com>
Reviewed-on: http://openocd.zylin.com/1349
Reviewed-by: Øyvind Harboe <oyvindharboe@gmail.com>
Tested-by: jenkins

README

@@ -434,7 +434,7 @@ Using the GIT command line client, you might use the following command
 to set up a local copy of the current repository (make sure there is no
 directory called "openocd" in the current directory):
 
-   git clone git://git.code.sf.net/p/openocd/code
+   git clone git://git.code.sf.net/p/openocd/code openocd
 
 Then you can update that at your convenience using