JDBC requests in a Transaction Controller not use the same connection。

**hdchild** ([Bug 66261](https://bz.apache.org/bugzilla//show_bug.cgi?id=66261&redirect=false)):
JDBC requests in a Transaction Controller not use the same connection。

I configure "JDBC connection Configuration" with Auto Commit = False.
I configure some JDBC requests in a Transaction Controller, I found 2 things:
1. each JDBC request in a Transaction Controller may use different connection instead of use the same connection.
2. At the end of test, jmeter will send "rollback" to all related connections.

The jmx file is uploaded

Created attachment [yizhixing_script_10_11_12%20%281%29.jmx](https://apache.github.io/jmeter-bugzilla-attachments/61/66261/38388/yizhixing_script_10_11_12%2520%25281%2529.jmx): the test plan jmx file

Severity: normal
OS: