MINOR: checks: Support list of status codes on http-check expect rules

MINOR: checks: Support list of status codes on http-check expect rules

It is now possible to match on a comma-separated list of status codes or range
of codes. In addtion, instead of a string comparison to match the response's
status code, a integer comparison is performed. Here is an example:

  http-check expect status 200,201,300-310