Fix TJ's assert error

Unable to reproduce but connect's "make test TESTS=test/static.test.js" does
it occasionally.

lib/http.js

@@ -1089,7 +1089,11 @@ function connectionListener(socket) {
     // When we're finished writing the response, check if this is the last
     // respose, if so destroy the socket.
     res.on('finish', function() {
-      assert(incoming[0] === req);
+      // Usually the first incoming element should be our request.  it may
+      // be that in the case abortIncoming() was called that the incoming
+      // array will be empty.
+      assert(incoming.length == 0 || incoming[0] === req);
+
       incoming.shift();
 
       res.detachSocket(socket);