Ensure changes-feed parser state is reset when new request starts
Ensure changes-feed parser state is reset when new request starts

It wasn't getting reset on some non-fatal errors, which meant that on
the next retry it would start off in mid-parse, causing more errors.

Fixes #1403

amco/couchbase-lite-ios,amco/couchbase-lite-ios,couchbase/couchbase-lite-ios,couchbase/couchbase-lite-ios,couchbase/couchbase-lite-ios,amco/couchbase-lite-ios,amco/couchbase-lite-ios,couchbase/couchbase-lite-ios,amco/couchbase-lite-ios,amco/couchbase-lite-ios,couchbase/couchbase-lite-ios,couchbase/couchbase-lite-ios,amco/couchbase-lite-ios