[Libvir] Re-factor sexpr_uuid method

The sexpr_uuid method is used to convert from the printable representation of a UUID into the binary format (unsigned char[16]). This patch refactors the main body of the method so that it is usable by other non-XenD driver backends for parsing UUIDs. This new re-factored method will be used by a patch I'll shortly submit for the test driver backend. Dan. -- |=- Red Hat, Engineering, Emerging Technologies, Boston. +1 978 392 2496 -=| |=- Perl modules: http://search.cpan.org/~danberr/ -=| |=- Projects: http://freshmeat.net/~danielpb/ -=| |=- GnuPG: 7D3B9505 F3C9 553F A1DA 4AC2 5648 23C1 B3DF F742 7D3B 9505 -=|