udevd: fix memory leak

Re: b99028c96307e729303be8f6750418979a7488b9 shrink struct udev_event

TEST 136: test multi matches 2
device '/devices/pci0000:00/0000:00:1d.7/usb5/5-2/5-2:1.0/tty/ttyACM0' expecting node 'right' =15011=
=15011= 7 bytes in 1 blocks are definitely lost in loss record 1 of 1

=15011=    at 0x47F9AB8: malloc (vg_replace_malloc.c:207)
=15011=    by 0x489CB5F: strdup (in /lib32/libc-2.7.so)
=15011=    by 0x8050F40: udev_rules_apply_to_event (udev-rules.c:1973)
=15011=    by 0x804A658: udev_event_execute_rules (udev-event.c:549)
=15011=    by 0x805A636: main (test-udev.c:100)
add:         ok
=15012=
=15012= 7 bytes in 1 blocks are definitely lost in loss record 1 of 1
=15012=    at 0x47F1AB8: malloc (vg_replace_malloc.c:207)
=15012=    by 0x4898B5F: strdup (in /lib32/libc-2.7.so)
=15012=    by 0x8050F40: udev_rules_apply_to_event (udev-rules.c:1973)
=15012=    by 0x804A9DF: udev_event_execute_rules (udev-event.c:658)
=15012=    by 0x805A636: main (test-udev.c:100)

remove: ok

index 19ee06d..55e27b7 100644
@@ -1970,6 +1970,7 @@ int udev_rules_apply_to_event(struct udev_rules *rules, struct udev_event *event
 					count = util_replace_chars(name_str, ALLOWED_CHARS_FILE);
 					if (count > 0)
 						info(event->udev, "%i character(s) replaced\n", count);
+					free(event->name);
 					event->name = strdup(name_str);
 				}
 				break;