cmd/storeserver: remove need for rc file
cmd/storeserver: remove need for rc file

Instead, use an endpoint flag to initialize the service.
This will make it easier to use and test.

Change-Id: Ib3456903b9905c65ca1159fb90356342d9d8c80e
Reviewed-on: https://upspin-review.git.corp.google.com/1920
Reviewed-by: Eduardo Pinheiro <55040cbb39ba395339ae7940d8da6cd97797a4a8@google.com>

upspin/upspin,upspin/upspin