Ignore the result of the list comprehension.

Resolves:

riak_kv_wm_crdt.erl:390: Expression produces a value of type [any()], but this value is unmatched
Ignore missing callback information.

Pipe is not using the R15+ style callbacks yet, so ignore warnings.
Ignore result of supervisor calls.

Resolves:

riak_kv_mrc_pipe.erl:287: Expression produces a value of type 'ok' | {'error','not_found' | 'simple_one_for_one'}, but this value is unmatched
riak_kv_mrc_pipe.erl:876: Expression produces a value of type 'ok' | {'error','not_found' | 'simple_one_for_one'}, but this value is unmatched
Ignore the result of list comprehensions.

Resolves:

riak_kv_mrc_pipe.erl:1020: Expression produces a value of type [any()], but this value is unmatched
riak_kv_mrc_pipe.erl:1024: Expression produces a value of type [any()], but this value is unmatched