evolve: remove the old functions for writing evolvestate
Previous patch made all the users of these functions to use the evolvestate
class and now they are not required. Let's remove them.
evolve: use the new evolvestate class in place of old methods
Earlier we had three methods, which used to handle all the storage around the
evolvestate but in previous patch we have introduced an evolvestate class
wrapper which can serve for all our needs. This patch replaces the existing
usage of the evolvestate with the new class introduced.
Upcoming patches will start using the class at more places.