obs/generic/: Support fluentbit-plugin-wendelin as a separate tarball. Fix some bugs and update files.

obs/generic/templates/compilation-templates/mca/Makefile.in: Support fluentbit-plugin-wendelin as a separate tarball.

obs/generic/: Fix some bugs. Update files.

build-scripts/clean_build_tree.sh: Fix failure when $RUN_BUILDOUT_DIR/go did not exist.
build-scripts/bootstrap_buildout.sh: Fix a bug in the backup mechanism.
templates/:
- Fix mca/Makefile.in
- Change debian_defaults/dirs.in to fit the mca case.