generate-config: make the nginx template filter unsupported directives
generate-config: make unsupported directive functionality available to other templates
Revert "generate-config: make unsupported directive functionality available to other templates"

This reverts commit dc97039c6c26781aa5baf9fbd1db36fb73af868e.
generate-config: don't mix tabs and spaces
Merge pull request #174 from pagespeed/oschaaf-generate-config-unsupported-directives

generate config: don't filter unsupported pagespeed directives in .pyconf files