Remove the gnu parameter from concat

Previously, the concatfragments.sh script was would default to using
GNU-specific flags for find, sort, and xargs. This necessitated
explicit passing of a "gnu = false" parameter to the concat define in
order to successfully run the script without GNU-specific flags when
working with systems that do not by default include GNU versions of the
utilities (solaris, for example).

This commit modifies the concatfragments script such that GNU versions
of the utilities are not needed at all. It does this while preserving
the original use case for the GNU flags, which was to allow special
characters (like spaces) in the filenames, which it accomplished by
using GNU flags to separate fields using null characters instead of
newlines.

In order to preserve backwards-compatibility with existing puppet
installations that make use of the "gnu = false" parameter, the
parameter list for the concat define has not been changed. Rather, the
gnu parameter is now deprecated and ignored.
Merge pull request #17 from pdxcat/refactor_remove_gnuflag

Remove the gnu parameter from concat
Update temporary files even when running in 'noop' mode
Suppress log messages when updating temporary files
Properly execute 'concatfragments.sh' even when '$concatdir' is mounted with 'noexec' flag