[trac388] Enable port config test in resolver

It needed to close sockets to be able to successfully roll back in case
of failure.

src/bin/resolver/tests/resolver_config_unittest.cc

@@ -174,7 +174,7 @@ TEST_F(ResolverConfig, listenAddresses) {
     EXPECT_TRUE(server.getListenAddresses().empty());
 }
 
-TEST_F(ResolverConfig, DISABLED_listenAddressConfig) {
+TEST_F(ResolverConfig, listenAddressConfig) {
     // Try putting there some address
     ElementPtr config(Element::fromJSON("{"
         "\"listen_on\": ["
@@ -192,9 +192,6 @@ TEST_F(ResolverConfig, DISABLED_listenAddressConfig) {
 
     // As this is example address, the machine should not have it on
     // any interface
-    // FIXME: This test aborts, because it tries to rollback and
-    //     it is impossible, since the sockets are not closed.
-    //     Once #388 is solved, enable this test.
     config = Element::fromJSON("{"
         "\"listen_on\": ["
         "   {"