Integration Tests should use --default-file for mysql commands

[mwr]

In Magento\TestFramework\Db\Mysql for all mysql commands --defaults-extra-file is used to define a custom .cnf file providing the mysql configuration.
Problem is, that the cnf-file provided using the parameter --default-extra-file is overwriten by a configuration under ~/my.cnf. Thus resulting in a invalid mysql connection configuration and furthermore the tests will fail.
To prevent an error due this issue, this pull request will change the parameter to --defaults-file which is not overwritten by other configuration files.

Also see mysql docs here: http://dev.mysql.com/doc/refman/5.7/en/mysqldump.html#option_mysqldump_defaults-extra-file

[arkadiych]

@mwr, you should sign Contributor License Agreement.

[mwr]

I've done that, but it still shows "not signed yet"

[mwr]

in my other pull request it is recognized correctly, strange.

#3440

[okorshenko]

I've done that, but it still shows "not signed yet"

@mwr , thank you for letting us know. We will analyze this issue

[Zatara7]

@mwr Could you please provide some examples of when this error happened?

[mwr]

Well whenever you are using a different mysql connection than defined in your ~/my.cnf.
We had this issue on our build, dev and staging environment, where we have like 2 or 3 different mysql versions on the same machine or within a docker container or on a completely different machine.

So this patch ensures the usage of the generated cnf file for integration tests.

[okorshenko]

@mwr Your Pull Request merged to develop branch. Thank you for contribution!

[mwr]

@jsiefer the problem was that the file provided via the parameter --default-extra-file is overwritten by a ~/my.cnf file. So basically the configuration provided with --default-extra-file was ignored and the one in ~/my.cnf was preferred, which is not what is expected in this scenario.