Fix issues: H402 one line docstring needs punctuation, W503 line break before binary operator. Change-Id: Ie93430898403f137e7b647a97a28b0d7a4ebb463
set/unset command classes should inherit from cliff.Command class. Also, this patch adds functional tests for compute agent. Change-Id: I25eafffd1167f82aa0d430628c22dee7516b1e19 Partial-Bug: 1546065