Fix type handling

Both the guts of the PuppetBind::Provider::Nsupdate module and the type method
of the dns_rr(nsupdate) provider produce and expect the type expressed as a
string, but the resource_record(nsupdate) provider's type method produces
symbols. This accidentally worked for a while, then it didn't. Also, in
quoted_type? that's supposed to be an array of strings, not a quoted string.

lib/puppet_bind/provider/nsupdate.rb

@@ -71,7 +71,7 @@ module PuppetBind
       end
 
       def quoted_type?(type)
-        %(TXT SPF).include?(type)
+        %w(TXT SPF).include?(type)
       end
 
       def maybe_quote(type, datum)