Replace Zend_Log with Psr\Log\LoggerInterface

[tdgroot]

Replace Zend_Log with Psr\Log\LoggerInterface to prepare for upgrade to higher ZF versions.

Description

I replaced Zend_Log with Psr\Log\LoggerInterface in Magento Framework.

To simplify the conversion I changed method call
$logger->log($message, \Zend_Log::INFO)
into
$logger->info($message).

Obviously, I had to change the ShellTest a bit to make it compatible with the Psr\Log\LoggerInterface.

Fixed Issues

1. Upgrade ZF components. Zend_Log #9237: Upgrade ZF components. Zend_Log

Testing scenarios

Run the unit test \Magento\Framework\Test\Unit\ShellTest.

Contribution checklist

• Pull request has a meaningful description of its purpose
• All commits are accompanied by meaningful commit messages
• All new or changed code is covered with unit/integration tests (if applicable)
• All automated tests passed successfully (all builds on Travis CI are green)

[magento-cicd2]

All committers have signed the CLA.

[okorshenko]

Hi @tdgroot
Thank you for your contribution. Unfortunately we have a fatal error caused by this PR here:
Could you please align your implementation with client code?

Please, look at this file: https://github.com/magento/magento2/blob/develop/dev/tests/api-functional/framework/bootstrap.php#L28

[tdgroot]

Hey @okorshenko

The fatal error happenened in the bootstrap of the integration test as well.
I refactored the logger code and also made the integration bootstrap file look a bit more like the api-functional bootstrap file.

[magento-team]

@tdgroot Thank you for the contribution