Prevent time field converting zones in changes 'was'

[adz]

When changing "Time" attributes the old '_was' value (e.g. bonus_time_was) will be converted based on zone. However, in all other cases "Time" attributes do not convert zones.

The expected behaviour is to NOT convert zones due to variations across dates, even within a single zone -- see more discussion here: #3145 (comment)

Original commit added here: 36129f2

Dirty datetime attributes should be aware of time zone info

Then later removed in commit slated for rails 4.(?) cb400b0

remove unnecessary code
it was added in 36129f2
but isn't useful anymore as corresponding tests pass without it

I've made the PR to rails 3-2-stable since rails 4+ seems to have rearranged the dirty.rb file considerably.

[sgrif]

Thank you very much for your work on this. Does this issue happen on 4.1 or 4.0? We do not accept bug fixes for the 3.x line at this time.

[adz]

I don't believe it happens in 4.0+.

I wasn't aware that 3.2 was totally dropped in support. Ouch. Will have to track a fork till we can upgrade our mono-rail.

Thanks for your review -- closing.