fix https://github.com/ytti/oxidized/issues/2544

[athompson-merlin]

50% of time zones have negative offsets, not positive.

[dMailonG]

@wk or @ytti, this fix would be greatly appreciated.

Last Update listed sometimes in UTC sometimes in local timezone last changed“modifiy to localtime and timezone UTC/Localtime in /nodes Dates column on Versions page is incorrect

[athompson-merlin]

50% of time zones have negative offsets, not positive.

FWIW, this statement (that I made, sadly) is quite inaccurate.

There are somewhere around 38 timezones with significant populations[1], ranging from UTC-12 to UTC+14. You know you want to know... Meanwhile, over half the humans alive today live in UTC+7 and UTC+8. TZs from UTC-2 through UTC-12 appear to have disproportionately fewer humans compared to the UTC[+0,+14] range.

I still can't believe I'm the first person in the Americas using this code in their local TZ, not UTC, who cared enough about it to track down the problem and submit a PR.

[1] https://blog.cyberclip.com/world-population-by-time-zone