Hybris 5.5.1 ant production fails

[christoph_probst]

under hybris 5.5.1 ant production fails with following error if accelerator is included

 [yvalidateantproduction] Validating: hybrisServer-Platform.zip
 [yvalidateantproduction] Validating: hybrisServer-AllExtensions.zip
 [yvalidateantproduction] done with 3 errors
 [yvalidateantproduction] ERRORS:
 [yvalidateantproduction] hybris/bin/ext-accelerator/acceleratorstorefrontcommons/commonweb/testsrc/ directory should NOT be included!
 [yvalidateantproduction] hybris/bin/ext-addon/b2ccheckoutaddon/acceleratoraddon/web/testsrc/ directory should NOT be included!
 [yvalidateantproduction] hybris/bin/ext-commerce/basecommerce/resources/testsrc/ directory should NOT be included!

[former_member1336901]

A Hybris bug has already been opened for this issue: https://jira.hybris.com/browse/ECP-479

However, there is only the workaround (as described above) so far. What needs to be done to fix the root cause of the problem (inclusion of the "testsrc" folders during "ant production")?