Don't assert ethwe carrier via the proxy

The test script runs commands inside containers via docker exec to
ensure the ethwe carrier is up. We must not run these commands via the
proxy because it will interpose weavewait, which will block forever if
attachment has failed (e.g. due to #1556).

test/640_proxy_restart_reattaches_test.sh

@@ -7,7 +7,7 @@ C2=10.2.0.34
 NAME=seetwo.weave.local
 
 check_attached() {
-    assert_raises "proxy exec_on $HOST1 c2 $CHECK_ETHWE_UP"
+    assert_raises "exec_on $HOST1 c2 $CHECK_ETHWE_UP"
     assert_dns_record $HOST1 c1 $NAME $C2
 }
 
@@ -51,6 +51,6 @@ check_attached
 proxy_start_container $HOST1 -di --name=c3 --restart=always # Use ipam, so it won't be attachable w/o weave
 weave_on $HOST1 stop
 weave_on $HOST1 launch-proxy
-assert_raises "proxy exec_on $HOST1 c3 $CHECK_ETHWE_UP"
+assert_raises "exec_on $HOST1 c3 $CHECK_ETHWE_UP"
 
 end_suite