Use the simpler command line syntax in the Debian init script

It's definitely not a blocker, but it would be nice to be consistent.

Closes #5033
Added missing percolate API parameters (percolate_routing, percolate_preference) to the REST API Spec

Closes #7173
[ENGINE] Add current translog ID to commit meta before closing

Today we simply close the IW when we have to open a new one if ie.
we change merge settings. Yet, the API is deprecated and under the hood
it commits the IW. For safety we should add the current translog ID and
use rollback instead to not wait for merges.
s/MapBuilder/singletonMap in InternalEngine
Tests: stop printing all thread stacks on failure: it's too noisy
Test: fix test to optimize and flush in the end to try to prevent 'Delete Index failed - not acked'
Completion Suggester: Fix CompletionFieldMapper to correctly parse weight
 - Allows weight to be defined as a string representation of a positive integer

closes #8090
[TEST] initialize SUITE | GLOBAL scope cluster in a private random context

Today any call to the current randomized context modifies the random
sequence such that cluster initialization is context dependent. If due
to an error for instance a static util method is used like `randomLong`
inside the TestCluster instead of the provided Random instance all
reproducibility guarantees are gone. This commit adds a safe mechanism
to initialize these clusters even if a static helper is used. All none
test scope clusters are now initialized in a private randomized context.