networkxml2conftest: Don't leak dnsmasq capabilities

==18324== 32 bytes in 1 blocks are still reachable in loss record 41 of 114
==18324==    at 0x4C2C070: calloc (vg_replace_malloc.c:623)
==18324==    by 0x4EA479B: virAlloc (viralloc.c:144)
==18324==    by 0x4EA674A: virBitmapNewQuiet (virbitmap.c:77)
==18324==    by 0x4EA67F7: virBitmapNew (virbitmap.c:106)
==18324==    by 0x4EC777D: dnsmasqCapsNewEmpty (virdnsmasq.c:801)
==18324==    by 0x4EC781B: dnsmasqCapsNewFromBuffer (virdnsmasq.c:815)
==18324==    by 0x407CF4: mymain (networkxml2conftest.c:99)
==18324==    by 0x409CF0: virTestMain (testutils.c:982)
==18324==    by 0x4080EA: main (networkxml2conftest.c:136)
Signed-off-by: NMichal Privoznik <mprivozn@redhat.com>

tests/networkxml2conftest.c

@@ -128,6 +128,10 @@ mymain(void)
     DO_TEST("dhcp6-nat-network", dhcpv6);
     DO_TEST("dhcp6host-routed-network", dhcpv6);
 
+    virObjectUnref(dhcpv6);
+    virObjectUnref(full);
+    virObjectUnref(restricted);
+
     return ret == 0 ? EXIT_SUCCESS : EXIT_FAILURE;
 }