Docs: Update plugins.asciidoc to fix typo

Changed the name of the European Environment Agency (from European Environmental Agency)

Closes #6807
Add local node to cluster state
Today, the tribe node needs the local node so it adds it when it starts, but other APIs would benefit from adding the local node, also, adding the local node should be done in a cleaner manner, where it belongs, which is right after the discovery service starts in the cluster service
closes #6811
[STORE]: Make use of Lucene build-in checksums

Since Lucene version 4.8 each file has a checksum written as it's
footer. We used to calculate the checksums for all files transparently
on the filesystem layer (Directory / Store) which is now not necessary
anymore. This commit makes use of the new checksums in a backwards
compatible way such that files written with the old checksum mechanism
are still compared against the corresponding Alder32 checksum while
newer files are compared against the Lucene build in CRC32 checksum.

Since now every written file is checksummed by default this commit
also verifies the checksum for files during recovery and restore if
applicable.

Closes #5924

This commit also has a fix for #6808 since the added tests in
`CorruptedFileTest.java` exposed the issue.

Closes #6808
[TEST] Subclass ElasticsearchTestCase in LoggingConfigurationTests
[TEST] Close TransportClient after it's used in BulkProcessorTests otherwise it will leave threads behind
[TEST] Do RollingUpgrade in BWC tests
[TEST] added ability to provide settings for external nodes in backwards compatibility tests

Closes #6809
[TEST] Wait for longer on slow nodes until replicating has kicked in
[STORE] Treat reading past EOF as an corrupted index when we fail to read segment infos
Aggregations: DateHistogramBuilder accepts String preOffset and postOffset

This is what DateHistogramParser expects so will enable the builder to build valid requests using these variables.
Also added tests for preOffset and postOffset since these tests did not exist

Closes #5586
[TEST] Fold SuggestActionTest into SuggestSearchTests

Instead of running the tests twice this commit just randomizes the API
that we use to return the suggestions.
Improve handling of failed primary replica handling
Out of #6808, we improved the handling of a primary failing to make sure replicas that are initializing are properly failed as well. After double checking it, it has 2 problems, the first, if the same shard routing is failed again, there is no protection that we don't apply the failure (which we do in failed shard cases), and the other was that we already tried to handle it (wrongly) in the elect primary method.
This change fixes the handling to work correctly in the elect primary method, and adds unit tests to verify the behavior
closes #6816
Do not ignore ConnectTransportException for shard replication operations

A ConnectTransportException should fail the replica shard

Closes #6183