tests: Increase unit test coverage for cc-check.go
tests: Increase unit test coverage for cc-check.go

Refactor part of TestCheckHostIsClearContainersCapable() into
setupCheckHostIsClearContainersCapable() and add a new test
TestCCCheckCLIFunction() to bring the unit test coverage for
cc-check.go to 100%.

Fixes #269.

Signed-off-by: James O. D. Hunt <348fbaadfbada55ea105602bf5609e23ac1c4898@intel.com>

clearcontainers/runtime,clearcontainers/runtime,chavafg/runtime,devimc/runtime,devimc/runtime,chavafg/runtime