Revert "[#23] Move to NetAddr::MAC for better handling of MACs"

This reverts commit 562b3d26db.

Discovered a few unpolished bits of NetAddr::MAC, unfortunately. For example
$NetAddr::MAC::errstr is not reset when new instances are created.

Netdisco/Makefile.PL

@@ -33,7 +33,7 @@ requires 'MCE' => 1.408;
 requires 'Net::Domain' => 1.23;
 requires 'Net::DNS' => 0.72;
 requires 'Net::LDAP' => 0;
-requires 'NetAddr::MAC' => 0.82;
+requires 'Net::MAC' => 2.103622;
 requires 'Net::NBName' => 0.26;
 requires 'NetAddr::IP' => 4.068;
 requires 'Opcode' => 1.07;