fix bugs in concurrency chapter, "A solution: Producer/Consumer" section

[prafulliu]

At the end of the _concurrency_ chapter, there is a demo named _A solution: Producer/Consumer_ has some bugs.

I also fixed them in Russian, Korea and Chinese.

val queue = new LinkedBlockingQueue[String]()    

But the other code use q for this instance, so it's an error.
2.

for (i <- i to cores) {

The second i is error, it should be 1.
3.

pool.submit(new IndexerConsumer[String](index, q))

index is not declared.

class Producer[T](path: String, queue: BlockingQueue[T]) extends Runnable {
  def run() {
    Source.fromFile(path, "utf-8").getLines.foreach { line =>
      queue.put(line)
    }
  }
}

val q = new LinkedBlockingQueue[String]()
val producer = new Producer[String]("users.txt", q)

queue.put(line) in Producer class will call an error.

error: type mismatch;
 found   : String("sssssssssss")
 required: T
    b.tell("sssssssssss")
               ^
one error found

Change it to

class Producer[T>:String](path: String, queue: BlockingQueue[T]) extends Runnable {

or

class Producer[T](path: String, queue: BlockingQueue[String]) extends Runnable {

can fix it.

[prafulliu]

fix link error in Finagle chapter, A link to "Finagle: A Protocol-Agnostic RPC System" is expired, I changed it to the new link in twitter's Engineering Blog. Also in other languages' translation.

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