title: ASIHTTPRequest setDownloadDestinationPath doesn't write file
body: <p>Consider the following code:</p>
  
  <pre><code>    ASIHTTPRequest *request = [ASIHTTPRequest requestWithURL:[NSURL URLWithString:@"http://192.168.2.71:3000/ios_file?filename=complaint&amp;folder=encounters&amp;id=3"]];
  NSString *mediaPath = [NSHomeDirectory() stringByAppendingPathComponent:@"Documents"];
  mediaPath = [mediaPath stringByAppendingPathComponent:@"complaint.MOV"];
  [request setDownloadDestinationPath:mediaPath];
  [request startSynchronous];
  NSLog(@"Got the file!");
  NSURL *theURL = [NSURL URLWithString:mediaPath];
  
  NSLog(@"Time to Play File!");
  NSLog(@"Filename is %@", [theURL absoluteString]);
  
  BOOL fileExists = [[NSFileManager defaultManager] fileExistsAtPath:[theURL absoluteString]];
  
  if (fileExists) {
      NSLog(@"THE FILE EXISTS ZOMG");
  }
  
  // Create file manager
  NSError *error;
  NSFileManager *fileMgr = [NSFileManager defaultManager];
  
  // Point to Document directory
  NSString *documentsDirectory = [NSHomeDirectory() stringByAppendingPathComponent:@"Documents"];
  
  // Write out the contents of home directory to console
  NSLog(@"Documents directory: %@", [fileMgr contentsOfDirectoryAtPath:documentsDirectory error:&amp;error]);
  </code></pre>
  
  <p>Returns the following:</p>
  
  <pre><code>2011-03-30 18:29:46.107 VideoCapture[158:707] Get recording from server
  2011-03-30 18:29:46.976 VideoCapture[158:707] Got the file!
  2011-03-30 18:29:46.978 VideoCapture[158:707] Time to Play File!
  2011-03-30 18:29:46.980 VideoCapture[158:707] Filename is /var/mobile/Applications/AE4B3091-3726-4FAE-B861-C4AE3616E743/Documents/complaint.MOV
  2011-03-30 18:29:46.986 VideoCapture[158:707] Documents directory: (null)
  </code></pre>
  
  <p>Going to the URL in question sends me a quicktime movie (I'm using Ruby's send_data File.read("#{file_path}.MOV"), :disposition => 'inline', :type => "video/quicktime").</p>
  
  <p>As you can see, there are no files in the directory! Help!</p>