arcyd fetch: flush output and adjust format

Ensure that you can tell which repo is being processed when running
'arcyd fetch' by flushing stdout before doing the slow operation.

Add a space before the ellipses ' ..' so it looks more like the repo
is being processed and less name has simply been truncated.

Test Plan:
$ ./precommit.sh
$ ./testbed/arcyd/test_shell.sh
    $ cd ../arcyd2
    $ arcyd fetch
arcyd fetch: print status before updating watcher

Let the user know what's happening before potentially blocking for a
while, when the repo snoop url cache is being updated.

Test Plan:
$ ./precommit.sh
$ ./testbed/arcyd/test_shell.sh
    $ cd ../arcyd2
    $ arcyd fetch