tox.ini: remove additionally missed mock deps
tox.ini: remove additionally missed mock deps

Ref: https://github.com/pytest-dev/pytest/pull/4415#discussion_r234452144

alfredodeza/pytest,hackebrot/pytest,Akasurde/pytest,The-Compiler/pytest,nicoddemus/pytest,nicoddemus/pytest,pytest-dev/pytest,tomviner/pytest,RonnyPfannschmidt/pytest,markshao/pytest,tomviner/pytest,The-Compiler/pytest