Remove inactive accounts from OWNERS: armansito, keybuk, rpaquay

These individuals are no longer performing reviews or submitting code
in the Chromium repository. Being in the OWNERS files confuses tools
such as git cl owners.

Review-Url: https://codereview.chromium.org/2030783002
Cr-Commit-Position: refs/heads/master@{#398938}
18 files changed