title: Converting DatePicker Date to UTC Format returns NULL
body: <p>I have 4 UITextfileds, start date, start time and end date, end time. Then I'm sending my date and time into my UTC function, but it's returning null.</p>
  
  <pre><code>NSString *str1 = _startDateField.text;
  str1 = [str1 stringByAppendingString:@" "];
  str1 = [str1 stringByAppendingString:_startTimeField.text];
  NSLog(@"str1 : %@", str1);
  NSString *str2 = _endDateField.text;
  str2 = [str2 stringByAppendingString:@" "];
  str2 = [str2 stringByAppendingString:_endTimeField.text];
  NSLog(@"str2 : %@", str2);
  // Convert string to date object
  NSDateFormatter *dateFormat = [[NSDateFormatter alloc] init];
  [dateFormat setDateFormat:@"dd-MMM-yyyy HH:mm"];
  NSDate *date1 = [dateFormat dateFromString:str1];
  NSDate *date2 = [dateFormat dateFromString:str2];
  NSLog(@"%@", date1);
  NSLog(@"%@", date2);
  NSString *startTime = [self getUTCFormateDate:date1];
  NSString *endTime = [self getUTCFormateDate:date2];
  NSLog(@"str1 : %@", startTime);
  NSLog(@"str2 : %@", endTime);
  </code></pre>
  
  <p><strong>Coverting to <code>UTC</code> format:</strong></p>
  
  <pre><code>-(NSString *)getUTCFormateDate:(NSDate *)localDate {
      NSLog(@"%@", localDate);
      NSDateFormatter *dateFormatter = [[NSDateFormatter alloc] init];
      NSTimeZone *timeZone = [NSTimeZone timeZoneWithName:@"UTC"];
      [dateFormatter setTimeZone:timeZone];
      [dateFormatter setDateFormat:@"dd-MMM-yyyy HH:mm"];
      NSString *dateString = [dateFormatter stringFromDate:localDate];
      NSLog(@"%@", dateString);
      return dateString;
  }
  </code></pre>
  
  <p>I want to read the date and time from my text fields and convert them into UTC format.</p>