Bump version to 6.5.4 (elastic#223)

Bump version to 6.5.3 (elastic#221)

Bump version to 6.5.2

Bump version to 6.5.1

Test only the numeric part of the process version (elastic#214)

When testing the version of the running Elasticsearch process,
don't consider suffix components like "-alpha1".

Fixes elastic#213

Bump to using JDK 11.0.1 (elastic#207)

The first patch release of JDK 11 is available. This commit bumps the
Docker images to use JDK 11.0.1 over JDK 11.

Bump version to 6.4.3 (elastic#203)

Bump version to 6.4.2 (elastic#196)

Fix handling of processors setting

Elasticsearch has a special setting called "processors" that is used to
configure the size of the internal threadpools, by telling Elasticsearch
to prentend that it is running on a system with the specified number of
processors rather than the detected number of processors. This should be
used in conjunction with actually limiting Elasticsearch to the
specified number of processors, via CPU pinning. However, this setting
does not currently work with the Docker image when configured via an
environment variable passed into the container. This is because the
logic for converting an environment variable into a setting assumes that
the setting must have at least two words separated by a dot. This is
close to correct, but not correct for the processors settings. This
commit adds special handling for the processors setting so that it can
be set via an environment variable.

Add test-snaphost Make target