Fix threading issue in CBLReplication -setCookieNamed: and deleteCookieNamed:
Fix threading issue in CBLReplication -setCookieNamed: and deleteCookieNamed:

- Rename _pendingCookies to _bg_pendingCookies.
- Wrap the code that access _bg_replicator and _bg_pendingCookies in the -tellReplicatorAndWait block.

lordkev/couchbase-lite-ios,lordkev/couchbase-lite-ios,tomco/couchbase-lite-ios,macoscope/couchbase-lite-ios,pellekrogholt/couchbase-lite-ios,brendand/couchbase-lite-ios,lordkev/couchbase-lite-ios,pegli/couchbase-lite-ios,brendand/couchbase-lite-ios,brendand/couchbase-lite-ios,amco/couchbase-lite-ios,pellekrogholt/couchbase-lite-ios,couchbase/couchbase-lite-ios,pegli/couchbase-lite-ios,amco/couchbase-lite-ios,brendand/couchbase-lite-ios,alfared/couchbase-lite-ios,ipmobiletech/couchbase-lite-ios,gotmyjobs/couchbase-lite-ios,amco/couchbase-lite-ios,gotmyjobs/couchbase-lite-ios,amco/couchbase-lite-ios,macoscope/couchbase-lite-ios,amco/couchbase-lite-ios,pellekrogholt/couchbase-lite-ios,amco/couchbase-lite-ios,gotmyjobs/couchbase-lite-ios,couchbase/couchbase-lite-ios,alfared/couchbase-lite-ios,lordkev/couchbase-lite-ios,pegli/couchbase-lite-ios,pegli/couchbase-lite-ios,pellekrogholt/couchbase-lite-ios,alfared/couchbase-lite-ios,gotmyjobs/couchbase-lite-ios,couchbase/couchbase-lite-ios,tomco/couchbase-lite-ios,macoscope/couchbase-lite-ios,macoscope/couchbase-lite-ios,couchbase/couchbase-lite-ios,amco/couchbase-lite-ios,couchbase/couchbase-lite-ios,tomco/couchbase-lite-ios,brendand/couchbase-lite-ios,couchbase/couchbase-lite-ios,tomco/couchbase-lite-ios,ipmobiletech/couchbase-lite-ios,ipmobiletech/couchbase-lite-ios,ipmobiletech/couchbase-lite-ios,alfared/couchbase-lite-ios