Remove deadcode

[jipjop]

Description

Removed unused dependencies from several classes. Got the warnings from the PHP CS Fixer.

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)

[orlangur]

Such kind of PR is useless as we can remove such occurrences all over the code automatically. 3fc476b looks like you do it manually.

The crux is that we don't enforce that no such new code appear currently. I believe we shall implement static test enforcing php-cs-fixer rules first and then do automatic fix of the whole codebase only once at a suitable moment.

[ishakhsuvarov]

@orlangur I totally agree, that we should remove automatically and enforce with the test, however:
While such occurrences exist there is no harm removing those in any possible way.

[vrann]

@jipjop Thank you for the contribution!

[orlangur]

@ishakhsuvarov I was mostly scared by manual nature of these changes :) It's ok to run unused_use fixer fully or partially but not safe to do same changes manually. Hope we have enough automation for changed files.