By default protobuffs doesn't create beams with debug info. This
causes issues when running dialyzer which requires debug info. Read
the `erl_opts` config and pass it down to protobuffs compiler.
This patch remedies an issue where the ebin directory would be
erroneously created as a file by the first "mv" command in
rebar_protobuffs_compile.erl [line 106] if the ebin file did not
exist at the root application level.
In essence, the patch ensures that the ebin directory exists at
the application directory level before any "mv" commands are
executed. The following code was inserted at line 106:
ok = filelib:ensure_dir(filename:join("ebin","dummy")),
