If you pass unicode multi-byte character to 'hypervisor-list'
and 'instance-usage-audit-log' commands using --matching
and --before options respectively, it returns keyerror.
This patch fixes these issues by encoding the host name and
date passed to the --matching and --before options
respectively.
Closes-Bug: #1804156
Change-Id: I9587af7e0fdd921fcaebe3e5c6c5bb40a9393e01