arcyd/test_shell: add a second repo

Make it possible to exercise multi-repo setups by introducing a second
repo into 'testbed/arcyd/test_shell.sh'

Test Plan:
$ ./testbed/arcyd/test_shell.sh
fixup! Arcyd: reduce restart time by caching urlwatcher

Closures capture the name of the variable, not the value - use
functools.partial to ensure that 'process_func' actually processes each
repo.

Test Plan:
$ ./precommit.sh
$ ./testbed/arcyd/acceptance_tests.sh

make sure both repos are processed in:
$ ./testbed/arcyd/test_shell.sh