src: switch from fnmatch to g_pattern_match_simple

src: switch from fnmatch to g_pattern_match_simple

The g_pattern_match function_simple is an acceptably close
approximation of fnmatch for libvirt's needs.

In contrast to fnmatch(), the '/' character can be matched
by the wildcards, there are no '[...]' character ranges and
'*' and '?' can not be escaped to include them literally in
a pattern.

Reviewed-by: Fabiano Fidêncio <fidencio@redhat.com>
Signed-off-by: Daniel P. Berrangé <berrange@redhat.com>