JAVA_OPTS for Bitbucket Server are incorrectly applied to bundled Elasticsearch

Summary

The setenv.sh script is called by the start-search.sh causing the JAVA_OPTS for Bitbucket Server to be used for Elasticsearch as well.

Steps to Reproduce

1. Start Bitbucket Server

Expected Results

The Java options for the Elasticsearch process are the expected ones.
For example, the following settings are used for the memory:

-Xms256m -Xmx1g

Actual Results

Elasticsearch uses the JAVA_OPTS from the Bitbucket Server process.
For example, the following settings are used for the memory, as well as the expected ones:

-Xms512m -Xmx768m ... -Xms256m -Xmx1g