Check if the connectFuture has completed successfully

[ajsutton]

PR description

When a connection is disconnected because it has no shared capabilities and we receive un uncompressed DISCONNECT message from the client, DeFramer incorrectly believes it still needs to disconnect the peer because it checked if the future had completed, but not if it had completed successfully.

Resulting exception:

Nov 21, 2018 12:39:44 PM io.netty.channel.AbstractChannelHandlerContext invokeExceptionCaught
WARNING: An exception 'java.util.concurrent.ExecutionException: tech.pegasys.pantheon.ethereum.p2p.netty.exceptions.IncompatiblePeerException: No shared capabilities' [enable DEBUG level for full stacktrace] was thrown by a user handler's exceptionCaught() method while ha
ndling the following exception:
io.netty.handler.codec.DecoderException: tech.pegasys.pantheon.ethereum.p2p.rlpx.framing.FramingException: Decompression failed
        at io.netty.handler.codec.ByteToMessageDecoder.callDecode(ByteToMessageDecoder.java:459)
        at io.netty.handler.codec.ByteToMessageDecoder.channelRead(ByteToMessageDecoder.java:265)
        at io.netty.channel.AbstractChannelHandlerContext.invokeChannelRead(AbstractChannelHandlerContext.java:362)
        at io.netty.channel.AbstractChannelHandlerContext.invokeChannelRead(AbstractChannelHandlerContext.java:348)
        at io.netty.channel.AbstractChannelHandlerContext.fireChannelRead(AbstractChannelHandlerContext.java:340)
        at io.netty.channel.DefaultChannelPipeline$HeadContext.channelRead(DefaultChannelPipeline.java:1359)
        at io.netty.channel.AbstractChannelHandlerContext.invokeChannelRead(AbstractChannelHandlerContext.java:362)
        at io.netty.channel.AbstractChannelHandlerContext.invokeChannelRead(AbstractChannelHandlerContext.java:348)
        at io.netty.channel.DefaultChannelPipeline.fireChannelRead(DefaultChannelPipeline.java:935)
        at io.netty.channel.nio.AbstractNioByteChannel$NioByteUnsafe.read(AbstractNioByteChannel.java:134)
        at io.netty.channel.nio.NioEventLoop.processSelectedKey(NioEventLoop.java:645)
        at io.netty.channel.nio.NioEventLoop.processSelectedKeysOptimized(NioEventLoop.java:580)
        at io.netty.channel.nio.NioEventLoop.processSelectedKeys(NioEventLoop.java:497)
        at io.netty.channel.nio.NioEventLoop.run(NioEventLoop.java:459)
        at io.netty.util.concurrent.SingleThreadEventExecutor$5.run(SingleThreadEventExecutor.java:858)
        at io.netty.util.concurrent.DefaultThreadFactory$DefaultRunnableDecorator.run(DefaultThreadFactory.java:138)
        at java.lang.Thread.run(Thread.java:748)
Caused by: tech.pegasys.pantheon.ethereum.p2p.rlpx.framing.FramingException: Decompression failed
        at tech.pegasys.pantheon.ethereum.p2p.rlpx.framing.Framer.processFrame(Framer.java:267)
        at tech.pegasys.pantheon.ethereum.p2p.rlpx.framing.Framer.deframe(Framer.java:155)
        at tech.pegasys.pantheon.ethereum.p2p.netty.DeFramer.decode(DeFramer.java:69)
        at io.netty.handler.codec.ByteToMessageDecoder.decodeRemovalReentryProtection(ByteToMessageDecoder.java:489)
        at io.netty.handler.codec.ByteToMessageDecoder.callDecode(ByteToMessageDecoder.java:428)
        ... 16 more
Caused by: org.iq80.snappy.CorruptionException: Recorded length is 449 bytes but actual length after decompression is 0 bytes
        at org.iq80.snappy.SnappyDecompressor.uncompress(SnappyDecompressor.java:55)
        at org.iq80.snappy.Snappy.uncompress(Snappy.java:85)
        at tech.pegasys.pantheon.ethereum.p2p.rlpx.framing.SnappyCompressor.decompress(SnappyCompressor.java:33)
        at tech.pegasys.pantheon.ethereum.p2p.rlpx.framing.Framer.processFrame(Framer.java:264)
        ... 20 more