Normalize return values of app_info data
Normalize return values of app_info data

The parsing functions were used inconsistently, and the returned values
were bad in some clauses; things only worked because they are never used
within rebar3. This ensures the return types are consistent on all
clauses.

tsloughter/rebar3,djnym/rebar3,rebar/rebar3,saleyn/rebar3,ferd/rebar3,erlang/rebar3,vladdu/rebar3,lrascao/rebar3,rebar/rebar3