Removed static versions of MatchAllDocsQuery

If a static cached version of MatchAllDocsQuery is used through for
instanst the `query_string` together with a boost like `*:*^2.0` the
globally used version is modified since queries are not immutable and it's
boost variable can change at any time. Holding on to queries that are modifiable
is risky and should not be done in a global scope.
This commit also adds tests for constant scores from `constant_score` query.

Closes #3521
Better exception handling in actions when forking to a thread pool
An execution on a thread pool might be rejected due to its settings, have better handling in those cases across the actions we have.
closes #3524
Added a debug log when sending an mapping updated request to master
reduce max replica in test to stabelize with low number of available nodes
Fix small javadoc typos for IndexShardRoutingTable
Added support for random_score function:

 * can be used to return matching results in random order

 Closes #1170