Don't throw exception if client immediately fails

This seems to cause an exception in `DistributedSuite#recover from repeated node failures during shuffle-reduce`.
I guess that the exception caused by having an invalid client is handled in a different way than the
client creation throwing an exception.

Author: aarondav

network/common/src/main/java/org/apache/spark/network/client/SluiceClientFactory.java

@@ -129,8 +129,6 @@ public void initChannel(SocketChannel ch) {
       // in the "inactive" state, and someone else simultaneously tried to create another client to
       // the same server. This is an error condition, as the first client failed to connect.
       throw new IllegalStateException("Client was unset! Must have been immediately inactive.");
-    } else if (!client.isActive()) {
-      throw new IllegalStateException("Failed to create active client.");
     }
     return client;
   }