pantsrc file paths are always unicode (#6316)
pantsrc file paths are always unicode (#6316)

This is a whack-a-mole until all options are always unicode, because
right now I can't run pants without this change :)
tdyas/pants,benjyw/pants,jsirois/pants,benjyw/pants,pantsbuild/pants,twitter/pants,benjyw/pants,pantsbuild/pants,tdyas/pants,tdyas/pants,benjyw/pants,wisechengyi/pants,twitter/pants,wisechengyi/pants,wisechengyi/pants,jsirois/pants,pantsbuild/pants,twitter/pants,twitter/pants,pantsbuild/pants,tdyas/pants,pantsbuild/pants,twitter/pants,tdyas/pants,tdyas/pants,pantsbuild/pants,wisechengyi/pants,benjyw/pants,wisechengyi/pants,benjyw/pants,twitter/pants,tdyas/pants,wisechengyi/pants,wisechengyi/pants,twitter/pants,pantsbuild/pants,twitter/pants,wisechengyi/pants,tdyas/pants,tdyas/pants,twitter/pants,benjyw/pants,jsirois/pants,wisechengyi/pants