do not create persistent name rules for KVM network interfaces

The virtual interfaces created by KVM are stable, 54:52:00 is the MAC-48
range of KVM.

extras/rule_generator/75-persistent-net-generator.rules

@@ -29,6 +29,9 @@ ENV{MATCHADDR}="$attr{address}"
 # match interface type
 ENV{MATCHIFTYPE}="$attr{type}"
 
+# ignore KVM virtual interfaces
+ENV{MATCHADDR}=="54:52:00:*", GOTO="persistent_net_generator_end"
+
 # These vendors are known to violate the local MAC address assignment scheme
 # Interlan, DEC (UNIBUS or QBUS), Apollo, Cisco, Racal-Datacom
 ENV{MATCHADDR}=="02:07:01:*", GOTO="globally_administered_whitelist"