Remove broken function.
Remove broken function.

config_generator.has_argparse could not work as
`f` does not exist in scope. Furthermore, I suspect it is
probably a duplication accident, as it's very similar
to source_parser.has_argparse, which is the only one
used in the codebase.

jschultz/Gooey,chriskiehl/Gooey,codingsnippets/Gooey,partrita/Gooey