Fix codecov reports for async module

[dominv]

Fix codecov reports for already existing tests in async module

(This issue comes from issue #280)

[dominv]

After checking that, in the locally generated reports, the coverage is 100% for this module and not having found any possible solution to this issue, an email has been sent to Codecov's Support and currently I'm waiting for an answer.

[dominv]

20/07 - Response received from support indicating the module is missed in Codecov.
21/07 - New email informing that the module appears in Codecov and attaching travis' logs with referred to the upload in Codecov. Requested a new solution.
01/08 - New contact to check if there is a solution for this issue.

[dominv]

I've double checked that the reports are generated locally and in Travis CI. They're detected by the Codecov script to be uploaded to Codecov's S3 but they still don't appear in Codecov site. I've contacted again with their support to ask for help about how to solve this.

[dominv]

I've checked that the reports are correctly generated in travis and detected by the script to be uploaded in Codecov's S3. Later, in Codecov detected modules, the async module is missing. It seems to be some problem uploading the files in S3 but we don't have access to what has been uploaded. Codecov's support has confirmed me that this seems to be the problem and they're investigating it.