rspec-daemon won't shut down with a single C-c

With a single C-c, `rspec-daemon` gets stuck with `RSpec is shutting down and will print the summary report` in my environment. Sending another C-c will shut down rspec-daemon.

```
% bundle exec rspec-daemon
Listening on tcp://0.0.0.0:3002
(snip)
^C
RSpec is shutting down and will print the summary report... Interrupt again to force quit.

```