Fix batch operations sample in reference docs
Fix batch operations sample in reference docs

Remove superfluous code from the sample in section 13.4.3 of the
JDBC reference guide.

Issue: SPR-9937

spring-projects/spring-framework,spring-projects/spring-framework,spring-projects/spring-framework,spring-projects/spring-framework,spring-projects/spring-framework,spring-projects/spring-framework,spring-projects/spring-framework