rose.config_processors.file: improve table create

Check whether required tables exist, instead of whether the database
file exists.
Also fixed various problems reported by pylint.
Merge pull request #1225 from matthewrmshin/fix-file-install-bad-db-schema

rose.config_processors.file: improve table create
rose config --print-conf: print result as conf

Allow output to be concatenated into another Rose configuration file.