There is no need to write the pidfile in the bin/elasticsearchshell script
as this happens already in the java code.
Also cleaning up the bin/elasticsearch shell script a bit (no need to return
an error code when exec is called, as this forks and exits the shell script
immediately).
Closes#3529Closes#1745
This decision helps people who want to rollout the oracle java without having an openjdk java installed.
* Removed any hard dependency on Java in the debian package
* The debian init script does not check for an existing JAVA_HOME anymore
* Debian and RedHat initscripts now exit if they do not find a java binary (instead of starting elasticsearch in the background and swallowing the error as there is no way to log it in that case)
* Changed the debian init script to rely on the pid file instead of the argument name of process
* Added a useful error message in case no java binary is available (in elasticsearch shell script)
Closes#3304Closes#3311