When invoking the elasticsearch-env.bat or x-pack-env.bat batch scripts
on Windows, if these scripts exits due to an error (e.g., Java can not
be found, or the wrong version of Java is found), then the script
exits. Sadly, on Windows, this does not also terminate the caller,
instead returning control. This means we have to explicitly exit so that
is what we do in this commit.
Relates elastic/x-pack-elasticsearch#2126
Original commit: elastic/x-pack-elasticsearch@18645db62c
a80b1e4de1