setup: sys.version_info always exists
It is documented as existing since Python 2.0, and empirically from
other OSS projects I maintain, there is no problem relying on its
existance.
filelog: fix parsemeta docstring
75bb7c702317 changed the return type of filelog.parsemeta but forgot to
update its docstring.
util: remove doc of long gone 'targetsize' argument
Gone since
fa836e050c50 (chunkbuffer: removed unused method and arg,
2007-10-11).