(ios) Move createIframeBridge to injectDeferredObject

Avoid failed script injections for pages which did not finish loading.
diff --git a/src/ios/CDVUIInAppBrowser.m b/src/ios/CDVUIInAppBrowser.m
index 5e3e900..d2cea12 100644
--- a/src/ios/CDVUIInAppBrowser.m
+++ b/src/ios/CDVUIInAppBrowser.m
@@ -362,6 +362,7 @@
 
 - (void)injectDeferredObject:(NSString*)source withWrapper:(NSString*)jsWrapper
 {
+    [self createIframeBridge];
     if (jsWrapper != nil) {
         NSData* jsonData = [NSJSONSerialization dataWithJSONObject:@[source] options:0 error:nil];
         NSString* sourceArrayString = [[NSString alloc] initWithData:jsonData encoding:NSUTF8StringEncoding];
@@ -564,7 +565,6 @@
 
 - (void)webViewDidFinishLoad:(UIWebView*)theWebView
 {
-    [self createIframeBridge];
     if (self.callbackId != nil) {
         // TODO: It would be more useful to return the URL the page is actually on (e.g. if it's been redirected).
         NSString* url = [self.inAppBrowserViewController.currentURL absoluteString];