This PR makes GetAllocs use a blocking query as well as adding a sanity
check to the clients watchAllocation code to ensure it gets the correct
allocations.
This PR fixes https://github.com/hashicorp/nomad/issues/2119 and
https://github.com/hashicorp/nomad/issues/2153.
The issue was that the client was talking to two different servers, one
to check which allocations to pull and the other to pull those
allocations. However the latter call was not with a blocking query and
thus the client would not retreive the allocations it requested.
The logging has been improved to make the problem more clear as well.
* Reverted changes to get methods
* Added prefix query parameter
* Updated node status to use prefix based searching
* Fixed tests
* Removed truncation logic
* Use go-memdb prefix indexer for lookups
* Add Job lookups
* Update state store with new ByIDPrefix get methods
* Call new methods when exact lookup fails or is not applicable
