Sync zoneinfo database with tzdata2011c from elsie.nci.nih.gov

Sync zoneinfo database with tzdata2011c from elsie.nci.nih.gov

leapseconds:    8.10 -> 8.11
northamerica:   8.40 -> 8.41
southamerica:   8.44 -> 8.45
zone.tab:       8.40 -> 8.41

* leapseconds: Update notice from IERS (no leap second at the end of
    June 2011).

* northamerica: Replace Juneau (Alaska) with Juneau, Sitka and
    Metlakatla.

* southamerica: Delay the end of the Chilean DST in 2011 until the
    first Sunday in April.

* zone.tab:  Replace Juneau (Alaska) with Juneau, Sitka and
    Metlakatla.