Hi, I'm a Linode customer and a Google employee. Several of Linode's blocks of IP addresses were definitely getting bogus geolocation results. Thanks to some help from Linode's support folks, I got all the blocks that had bogus entries reported internally at Google, and everything should be fixed.
Different applications at Google get geolocation data changes at different times, but most should show the changes in the next day or two, if they aren't already.
Finally, if you're a time traveler who has discovered this thread because Google thinks your IP address is in the wrong country, I'll roll up the helpful information already provided by community members:
If you go to http://www.google.com/ncr, that will never redirect based on geolocation, so that can be used as a temporary workaround.
Please report the bug to Google, as explained in this help article in the section "reporting incorrect IP detection".