title: Issue with NSDateFormetter iOS
body: <p>just figured out that NSDateFormatter stopped recognising AM/PM with 24 hour format. My code is </p>
  
  <pre><code>NSDateFormatter *dateFormatter = [[NSDateFormatter alloc] init];
  dateFormatter.dateFormat = @"yyyy MM dd HH:mma";
  
  NSDate *date1 = [dateFormatter dateFromString:@"2015 02 11 12:30PM"];
  NSLog(@"%@", date1);
  NSDate *date2 = [dateFormatter dateFromString:@"2015 02 11 13:30PM"];
  NSLog(@"%@", date2);
  </code></pre>
  
  <p>The output I got was showing same date is:</p>
  
  <pre><code>2015-12-24 15:38:54.234 xyz[580:88238] 2015-02-11 07:00:00 +0000
  2015-12-24 15:38:54.235 xyz[580:88238] 2015-02-11 07:00:00 +0000
  </code></pre>
  
  <p>But earlier it's working before i updated my XCode to 7.2 and my iPod to 9.2. Please let me know if it's an iOS 9.2 bug.</p>