Update p5-Date-Manip to 6.25.

Changes from previous:
VERSION 6.25 (2011−08−31)
    Relaxed one constraint in ISO 8601 dates
        A time separated by whitespace from the date can use a single digit
        hour.  Yuming Philip Xiang

    Set official removal dates for old config variables
        Config variables will be removed 2 years after they are deprecated
        (except for the TZ variable which, due to it's wide use, will be
        kept for 4 years).

    Time zone fixes
        Newest zoneinfo data (tzdata 2011i)

(hiramatsu)