(PUP-716) Fix up direct_file_server_spec after FileServer API change
(PUP-716) Fix up file_server_spec after FileSystem API change
(PUP-716) Fix up json_spec after FileSystem API change
(PUP-716) Fix up ssl_file_spec, yaml_spec after FileSystem API change
(PUP-716) Fix up unit/network specs after FileSystem API change
(maint) Add () around potentially problematic Ruby expression
(PUP-716) Fix up FileSystem API change, tests indirector, parser, node