fix reset_db would set OWNER = None with no db user

If you use postgresql, and you're lazy like I am and don't set a
username and let postgresql just use $USER, your settings.DATABASE_USER
will be `None`. This makes the existing code do this:

    Executing... "CREATE DATABASE db_name WITH OWNER = None ENCODING = 'UTF8' ;"

This change ignores WITH OWNER when there is no user.
style: make string concatenation whitespace leading

It's weird how it's all leading whitespace and then switches to trailing.

Also snuck in a change to remove unnecessary paren. Now that
line is almost under 80 cols wheee.
Merge pull request #304 from crccheck/resetdb-no-username

resetdb: fix reset_db would set OWNER = None with no db username for postgresql.