There are five options marked with TODOs:
* periodic_task_interval - negative values are valid, making the TODO
invalid
* host_subset_size - code was in-place to prevent negative values, so
replace this code with a min parameter
* isolated_images - removing this option requires a little bit of
thought and would likely require a blueprint. Retain this for now.
* max_instances_per_host, attestation_auth_timeout,
soft_affinity_weight_multiplier,
soft_anti_affinity_weight_multiplier - support funky value ranges
which, semantically speaking, shouldn't be allowed. Start logging
any "invalid" values.
Change-Id: I8871b628f0ab892830ceeede68db16948cb293c8