Field value of 'Validation Query' (JDBC Connection Configuration) is lost when saving test plan.

**patrick.trapp** ([Bug 62421](https://bz.apache.org/bugzilla//show_bug.cgi?id=62421&redirect=false)):
Steps to reproduce behavior:
- Add "JDBC Connection Configuration" to test plan
- change value of "Validation Query" to something like 'select 1 from dual'
- select "File / Save Test Plan as" from menu
- When the File dialog opens up, the Field value of "Validation Query" is reset.

Expected behavior:
- the Field value of "Validation Query" should keep it's assigned value when storing the Test Plan.

Severity: trivial
OS: All