Fix a bug on identifying that a feed already exists.

Google ID for feeds is the string "feed/" followed by the URL of the feed.
Don't be fooled by URLs having "feed/" inside them (like most Wordpress feeds)...

GoogleReader.m

@@ -486,7 +486,7 @@ -(void)completeLoadSubscriptions {
 		{
 			LOG_EXPR(feed);
 			NSString * feedID = [feed objectForKey:@"id"];
-			NSString * feedURL = [feedID stringByReplacingOccurrencesOfString:@"feed/" withString:@""];
+			NSString * feedURL = [feedID stringByReplacingOccurrencesOfString:@"feed/" withString:@"" options:NULL range:NSMakeRange(0, 5)];
 
 			NSString * folderName = nil;