fixed build_asf.sh so that the xapi version is not affected
Updating pom.xml version numbers for release 4.2.1

Signed-off-by: Abhinandan Prateek <aprateek@apache.org>
Revert "Updating pom.xml version numbers for release 4.2.1"

This reverts commit cc662445a52285d65607831cddb7b95e9f058b05.