Remove Diego-SSH plugin
Remove Diego-SSH plugin

This plugin is now deprecated as CLI v6.13.0 is out, which incorporates the SSH
commands.

cloudfoundry-incubator/cli-plugin-repo,guidowb/cli-plugin-repo,guidowb/cli-plugin-repo,brybwy/cli-plugin-repo,guidowb/cli-plugin-repo,kkellner/cli-plugin-repo,brybwy/cli-plugin-repo,guidowb/cli-plugin-repo,cloudfoundry-incubator/cli-plugin-repo,brybwy/cli-plugin-repo,brybwy/cli-plugin-repo,cloudfoundry-incubator/cli-plugin-repo,cloudfoundry-incubator/cli-plugin-repo,kkellner/cli-plugin-repo,kkellner/cli-plugin-repo