pbr 5.3.1 release + SVN and other customizations

This reflects pbr version 5.3.1 with all customizations merged in from branches changelog_filename, ignore_emails and svn

pbr 5.2.0 release + SVN and other customizations

This reflects pbr version 5.2.0 with all customizations merged in from branches changelog_filename, ignore_emails and svn

pbr 5.1.0 release + SVN and other customizations

This reflects pbr version 5.1.0 with all customizations merged in from branches changelog_filename, ignore_emails and svn