minor testbed fix

Author: aaustin

Branch-TestBed/Branch-TestBed/ViewController.m

@@ -66,7 +66,7 @@ - (IBAction)createBranchLinkButtonTouchUpInside:(id)sender {
     linkProperties.feature = feature;
     linkProperties.channel = channel;
     [linkProperties addControlParam:@"$desktop_url" withValue: desktop_url];
-    [linkProperties addControlParam:@"$ios_url" withValue: channel];
+    [linkProperties addControlParam:@"$ios_url" withValue: ios_url];
 
     [self.branchUniversalObject getShortUrlWithLinkProperties:linkProperties andCallback:^(NSString *url, NSError *error) {
         [self.branchLinkTextField setText:url];