Move upgrade directions for version < 1.5.0 to history document

The upgrading doc is huge. Most people don't need docs more than 10
years old. Move docs for versions less than 1.5.0 (July 2013) to
upgrading-history.txt.

Probably could cut this back to 5 years (1.6.0 release in 2018)
but lets go with 10 for now.

Author: rouilj