[proxy] Set hostname and domainname based on container name, when dns

Had to make the assert_dns_record test helper more robust against
'getent hosts' returning duplicates

test/630_proxy_dns_test.sh

@@ -4,15 +4,17 @@
 
 C1=10.2.0.78
 C2=10.2.0.34
-NAME=seetwo.weave.local
+C1_NAME=c1.weave.local
+C2_NAME=seetwo.weave.local
 
 start_suite "Proxy registers containers with dns"
 
 weave_on $HOST1 launch-dns 10.2.254.1/24
 weave_on $HOST1 launch-proxy --with-dns
-proxy docker_on $HOST1 run -e WEAVE_CIDR=$C2/24 -dt --name=c2 -h $NAME $SMALL_IMAGE /bin/sh
-proxy docker_on $HOST1 run -e WEAVE_CIDR=$C1/24 -dt --name=c1          $DNS_IMAGE   /bin/sh
+proxy docker_on $HOST1 run -e WEAVE_CIDR=$C2/24 -dt --name=c2 -h $C2_NAME $SMALL_IMAGE /bin/sh
+proxy docker_on $HOST1 run -e WEAVE_CIDR=$C1/24 -dt --name=c1             $DNS_IMAGE   /bin/sh
 
-assert_dns_record $HOST1 c1 $NAME $C2
+assert_dns_record $HOST1 c1 $C2_NAME $C2
+assert_dns_record $HOST1 c2 $C1_NAME $C1
 
 end_suite

test/config.sh

@@ -128,7 +128,7 @@ assert_dns_record() {
 
     [ -z "$DEBUG" ] || greyly echo "Checking whether the IPs '$@' exists at $host:$container"
     for ip in "$@" ; do
-        assert "exec_on $host $container getent hosts $ip | tr -s ' '" "$ip $name"
+        assert "exec_on $host $container getent hosts $ip | awk '{print \$2}'" "$name"
     done
 }