Isolate ruby environment and set java heap size

[jordansissel]

• Clear GEM_HOME and GEM_PATH variables to ensure we are only using
  the gems baked into the kibana jar and don't accidentally use
  the user/system's gem paths (Fixes Mixed ruby environment makes bin/kibana fail to load puma #1531)
• Set JVM heap size to 512m. If we don't do this, the default (for the
  common JVMs) is 25% of system ram, which is not a desirable default.

[jordansissel]

Testing this - failed.

Currently fails loading puma/puma_http11 but this file is a shared object (?) under here. Which is weird. I"m looking into how this got built so I can fix it.

% jar tf lib/kibana.jar | grep puma/puma
gems/puma-2.9.0/lib/puma/puma_http11.so

[jordansissel]

I seem to have resolved my build problem by having the environment ruby be jruby during grunt build - is this expected?

Either way, here's test results:

• master:

% bin/kibana
The Kibana Backend is starting up... be patient
LoadError: no such file to load -- puma/puma_http11

• this PR (success!)

% bin/kibana
The Kibana Backend is starting up... be patient
{"@timestamp":"2014-10-06T19:31:33+00:00","level":"INFO","name":"Kibana","message":"Kibana server started on tcp://0.0.0.0:5601 in production mode."}

[rashidkpc]

Yeah probably expected, since your system ruby is probably 2.1.x and jruby is 1.9.3 and thy probably don't share gems and such. We'll check out the pull!

[rashidkpc]

Typo here? KIBANA_VERSION => KIBANA_VERSIO

[jordansissel]

facepalm

[jordansissel]

Fixed and repushed as a single commit.

[w33ble]

I tried to test this, but I couldn't get the reported error to happen, no matter what local version of ruby I installed, so I couldn't verify that it goes away