[docs] Incorrect footnote in "15.3. time — Time access and conversions"

[John Haxby]

The footnote at the end of http://docs.python.org/library/time.html says
>
> [1]    [...] Also, a strict reading of the original 1982 RFC 822
> standard calls for a two-digit year (%y rather than %Y), but practice
> moved to 4-digit years long before the year 2000. The 4-digit year has
> been mandated by RFC 2822, which obsoletes RFC 822.

The change from 2 digit years to 4 digit years was actually mandated by
RFC 1123 in 1989

>
>       5.2.14  RFC-822 Date and Time Specification: RFC-822 Section 5
>
>          The syntax for the date is hereby changed to:
>
>             date = 1*2DIGIT month 2*4DIGIT
>
>          All mail software SHOULD use 4-digit years in dates, to ease
>          the transition to the next century.


It had to be "SHOULD" to give people time to update software. 
Thankfully, eleven years later, practically everyone had switched to
four digit years.

jch