title: NSMutableURLRequest setTimeoutInterval issue
body: <p>Ok firstly if I use a NSURLReuqest(non mutable) as following, the the connection do timeout accordingly to what was set.
  The weird thing is why does the NSLog always read 0?</p>
  
  <pre><code>self.requestURL = [NSURLRequest requestWithURL:[NSURL URLWithString:requestString]cachePolicy:NSURLRequestUseProtocolCachePolicy timeoutInterval:20.0];
  NSLog(@"request timeOutInterval:%d", self.requestURL.timeoutInterval); // always 0
  </code></pre>
  
  <p>Next, I do something like this and the timeoutInterval does not get set.</p>
  
  <pre><code>self.requestURL = [[[NSMutableURLRequest alloc] initWithURL:[NSURL URLWithString:requestString]] autorelease];
  [self.requestURL setTimeoutInterval:20];
  NSLog(@"request timeOutInterval:%i", self.requestURL.timeoutInterval); // same thing always 0 here.
  </code></pre>
  
  <p>EDIT. I am using %f to log the timeoutInterval property now and both reads 20.000. But the real problem is why was my my NSMutableURLRequest not firing the <code>- (void)connection:(NSURLConnection *)connection didFailWithError:(NSError *)error</code> delegate call back method when it reaches the timeoutInterval(20s). Instead it is only timed out at around the 75s. Even longer than the default of 60s...</p>
  
  <p>Even if I remove the <code>[self.requestURL setTimeoutInterval:20];</code> line, the connection still timeout at 75s.</p>
  
  <p>I have tried</p>
  
  <p><code>self.requestURL = [[[NSMutableURLRequest alloc] initWithURL:[NSURL URLWithString:requestString] cachePolicy:NSURLRequestUseProtocolCachePolicy timeoutInterval:20.0] autorelease];</code></p>