This generic and the associated method for a CURLHandle
allows one to reset the state of the Curl object
to its default state. This is convenient if we want
to reuse the same connection, but want to ensure
that it is in a particular state.
Unfortunately, we cannot query the state of different
fields in an existing Curl handle and so we need
to be able to reset the state and then update it with
any particular settings we would have liked to keep.