Fix duplicate module naming in edoc test suite data

[tolbrino]

The changes from #2040 would result in the Erlang compiler crashing under the following circumstance:
A set of source files with the same name, but in different source directories, would be compiled in parallel into the same target directory. This is the case for the utility apps used in the edoc test suite.

I suspect before the parallel compilation only one the of the 2 apps has actually been used.

An improvement to rebar_compiler_erl could be to preserve source sub-directories in the target directory structure.

cc @ferd
cc @max-au

[tolbrino]

@ferd Could you re-run the failed TravisCI job?

[ferd]

Yeah, duplicate module names are obviously a problem, so it's possible that the parallel builds made their order non-deterministic. It's fine to fix the test case with renames. Will merge once it passes.

[ferd]

Yeah I don't get why it keeps repeatedly failing on fetches. Can you rebase on master and see if something there is different to make it work?

[tolbrino]

Yeah I don't get why it keeps repeatedly failing on fetches. Can you rebase on master and see if something there is different to make it work?

Tried that, still not working.

[ferd]

This built fine on my own windows10 machine. I'll assume something is borked with the CI and merge.