fix function call typo causing no retry mechanism in ninja daemon startup

[dmoody256]

Fixed a silly typo which I am pretty sure is responsible for intermittent issues seen in the CI.

The ninja scons daemon server startup script will launch the daemon process, then attempt to connect to the server to make sure the server is running before exiting 0 (letting ninja know the server has started successfully). On slower systems the server may not respond fast enough and a connection refused will be issued. The client attempting to connect should retry in this situation in hopes the server is ready to respond in subsequent attempts to connect.

The startup script has this logic, and it will also not retry if the server process has been confirmed killed via subprocess.poll() = not None. The issue is that the code omitted the parenthesis's and anytime a retry was needed, it would immediately end prematurely in failure.

Contributor Checklist:

• I have created a new test or updated the unit tests to cover the new/changed functionality.
• I have updated CHANGES.txt (and read the README.rst)
• I have updated the appropriate documentation