Lightweight drop-in replacement for the xcat syncfiles postscript

This is intended for modern Linux distributions, and drops all of the legacy compatibility code in the original xcat code.

# cat syncfiles startsyncfiles startsyncfiles.awk startsyncfiles.aix | wc -l
237
# cat syncfilez | wc -l
33

Copy the script to /install/postscripts on the head node.

You can either replace syncfiles in the postscripts tab by using tabedit postscripts or add it to the osimage definition's postscript or postbootscript fields.