purge-distfiles: grep instead of sourcing template
purge-distfiles: grep instead of sourcing template

To catch all SHA256 hashes from a template, even the ones which
are used only under certain preconditions, use grep [0-9a-f]{64} to
find all hashes in a template.

The may be some false positives which does not hurt the intended
purpose to purge obsolete distfiles.

Signed-off-by: Jürgen Buchmüller <2642204b262fe30d9fcde46ee57f8ed7ac19ed92@t-online.de>

necrophcodr/void-packages,necrophcodr/void-packages,necrophcodr/void-packages,necrophcodr/void-packages,necrophcodr/void-packages