Fix Objective-C SampleCodeTest
Fix Objective-C SampleCodeTest

- Fixed a wrong method name which causes the duplication error.
- Fixed invalid data type.

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