Nightly: delete old builds not in branches list

Before starting the build process itself, the script will look in the
target directory for any old builds for branches that are not part of
the specified branches list, and delete them.

This ensures we only keep nightly builds for branches under active
development

Fixes #22642

nightly-builds.sh

@@ -52,6 +52,12 @@ cat <<-EOF >>$logfile
 
 EOF
 
+# Remove any builds not part of the branches list
+echo "$(date +'%F %T') Deleting old builds not part of branches list" |tee -a $logfile
+find $pathBuilds -maxdepth 1 -name 'mantisbt*' |
+	grep -vE -- "-(${branches//,/|})-[0-9a-f]{7}" |
+	xargs --no-run-if-empty rm -r 2>&1 |tee -a $logfile
+
 # Build the tarballs
 echo "$(date +'%F %T') Generating nightly builds for branches:"
 refList=$(eval echo origin/{$branches})