Update zoneinfo database.

Update zoneinfo database.

Theory:		7.15 -> 7.19
africa:		7.37 -> 7.39
antarctica:	7.24 -> 7.25
asia:		7.82 -> 7.85
australasia:	7.71 -> 7.73
backward:	7.27 -> 7.29
europe:		7.92 -> 7.95
leapseconds:	7.17 -> 7.20
northamerica:	7.74 -> 7.79
southamerica:	7.59 -> 7.61
zone.tab:	1.30 -> 1.32

Note: I had already updated leapseconds to include this year's leapsecond
      so we basically just change the comments' indenting here.