* Params improvements to Cluster Health API wait for shards
Previously, the cluster health API used a strictly numeric value
for `wait_for_active_shards`. However, with the introduction of
ActiveShardCount and the removal of write consistency level for
replication operations, `wait_for_active_shards` is used for
write operations to represent values for ActiveShardCount. This
commit moves the cluster health API's usage of `wait_for_active_shards`
to be consistent with its usage in the write operation APIs.
This commit also changes `wait_for_relocating_shards` from a
numeric value to a simple boolean value `wait_for_no_relocating_shards`
to set whether the cluster health operation should wait for
all relocating shards to complete relocation.
* Addresses code review comments
* Don't be lenient if `wait_for_relocating_shards` is set