allow hypervisors to be down but still pass

This test case is pretty raw, but it does make some invalid
assumptions about using the first hypervisor for everything. In
the uptime case it really needs to loop over all of them otherwise
if the first hypervisor is disabled this will fail.

This also does a cleanup refactoring of the hypervisor list check.

Change-Id: I9c3db794269f61aaaa55d432b14edf2d0fd1c774
Closes-Bug: #1193194
Fix the example of testr testing

Closes-Bug: #1263885

By separating the negative tests, the README example has not been valid.
This commit fix this.

Change-Id: I299618bb9da63b47af17efbe4ea226ebf770f86a
Merge "allow hypervisors to be down but still pass"
Merge "Fix the example of testr testing"