Revert "Allow for potential siblings in pattern match"
Revert "Allow for potential siblings in pattern match"

This reverts commit 3058b8e8dec5e818a79150a443b48658f7a0805e.

Performance: we do not expect timeseries data to have siblings
because the w1c write path does not retrieve existing objects
before writing updates. Including this change would significantly
increase the number of objects that would require a dict:find
invocation when is_ts/1 is invoked.

andytill/riak_kv