[7.1] IBM DB2 JDBC driver download URL needs updating

Pipeline test were faiing for the Configuration Guide. Investigation reveals that it is due to an outdated URL.

The "JDBC Driver Download Locations" (4557.adoc) lists the download URLs for the latest JDBC drivers for various vendors.

For IBM DB2, it list this URL: http://www-306.ibm.com/software/data/db2/java/

However, that redirects you to this page, which has no download information: https://www.ibm.com/support/knowledgecenter/SSEPGG_10.1.0/com.ibm.db2.luw.container.doc/doc/t0024244.html

A search shows that the drivers are available here: http://www-01.ibm.com/support/docview.wss?uid=swg21363866

We need to replace the invalid URL with the correct one.