tests: Add option to panic mock hook
tests: Add option to panic mock hook

Allow an extra argument to be specified to cause the mock hook
to panic after sleeping. This will be useful for tests to ensure
correct behaviour if the hook fails.

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

containers/virtcontainers,containers/virtcontainers