This commit adds a new configuration file jvm.options to centralize and
simplify management of JVM options. This separates the configuration of
the JVM from the packaging scripts (bin/elasticsearch*, bin/service.bat,
and init.d/elasticsearch) simplifying end-user operational management of
custom JVM options.
apart from locahost typo, the issue is that localhost is not 100% safe
for all distros with IPv6.
For example fedora23 defines localhost4 and localhost6 (among other
aliases) so `curl localhost:9200` doesn't work.
For this reason, I think it's safer to replace localhost with 127.0.0.1