removed psql's dbname argument where not required

Postgres throws an error if postgres.db is defined in config options and is added to the command line for query methods before the db exists.
This is a common occurrence when the postgres.db is still going to be created by the highstate.
I used the fact that None and False are different to simply omit the --dbname command line option to psql when db is set to False and then I set it to False for all methods that do not need this setting.