Monkey patch elasticsearch-env file so it parses on busybox.

[anuraaga]

While elasticsearch docs do mention a requirement on bash, so far we haven't had issues running on busybox. elastic/elasticsearch#49612 unfortunately broke compatibility at the syntax level.

This might give motivation to install bash into our image if it continues, let's try once to hack around it and see how far it gets us. At the same time, I see some movement to support busybox in elastic/elasticsearch#52519 so it could work out fine in the end.

Fixes #3042

[codefromthecrypt]

I'm tempted to simplify this as all the detection is moot since we are in a fixed image we control..

[codefromthecrypt]

you can rewind the last commits if you disagree, but I built locally and seems ok!

[codefromthecrypt]

oops spoke too soon.. the error about thai segmentation pops up late.

[codefromthecrypt]

[2020-03-25T06:29:14,994][ERROR][o.e.x.c.t.IndexTemplateRegistry] [zipkin-elasticsearch] error adding index template [ilm-history] from [/ilm-history.json] for [index_lifecycle]
java.lang.UnsupportedOperationException: This JRE does not have support for Thai segmentation
	at org.apache.lucene.analysis.th.ThaiTokenizer.<init>(ThaiTokenizer.java:70) ~[lucene-analyzers-common-8.4.0.jar:8.4.0 bc02ab906445fcf4e297f4ef00ab4a54fdd72ca2 - jpountz - 2019-12-19 20:16:38]
	at org.apache.lucene.analysis.th.ThaiTokenizer.<init>(ThaiTokenizer.java:63) ~[lucene-analyzers-common-8.4.0.jar:8.4.0 bc02ab906445fcf4e297f4ef00ab4a54fdd72ca2 - jpountz - 2019-12-19 20:16:38]