Zuul-cloner's behavior is to clone the repository into a subdirectory
under a directory named for the repo namespace. Git's default behavior
is to just clone it directly into the present working directory. This
patch adds an argument to the git clone command to clone it into the
<namespace>/<repo name> directory, so that whether zuul-cloner or git
is used the repo ends up in the same directory relative to the PWD.
Change-Id: Ice5d2d72a3dd674cd09171d480d3517b96dae2a5
e73073a120