clone: pass the remote name to remote_get

clone: pass the remote name to remote_get

Currently when using a remote helper to clone a repository, the
remote helper will be passed the url of the target repository as
first argument (which represents the name of the remote). This name
is extracted from transport->remote->name, which is set by
builtin/clone.c when it calls remote_get with argv[0] as argument.

Fix this by passing the name remote will be set up as instead.

However, setup_reference calls remote_get before the remote is
added to the config file. This will result in an improperly
configured remote (in memory) if later on remote_get is called
with an argument that is not equal to the initial remote_get call
in setup_reference. Fix this by delaying the remote_get call until
after the remote has been added to the config file.

Signed-off-by: Junio C Hamano <gitster@pobox.com>