Import of features - remaining estimate should default to the original estimate

I'm importing a set of new features. Each feature has a corresponding estimate. As part of
the import, the remaining estimate gets set to "Unknown". When a user begins logging time spent
on this feature, JIRA is not able to auto adjust the remaining estimate (presumably because
it can't subtract from "Unknown").

As a work around, the user must set the estimated time remaining correctly the first time
they log time spent on this feature. Once the remaining estimate is a number, the auto adjust
works as it should.

An improvement would be to set the remaining estimate to be the same as the original
estimate when the import is performed.