Silence analyzer warning for nil-checking NSNumber

Reviewed By: @jspahrsummers Differential Revision: D2503068

Author: javache

React/Base/RCTConvert.m

@@ -317,7 +317,7 @@ static void RCTConvertCGStructValue(const char *type, NSArray *fields, NSDiction
  for (NSString *alias in aliases) {
  NSString *key = aliases[alias];
  NSNumber *number = json[alias];
- if (number) {
+ if (number != nil) {
  RCTLogWarn(@"Using deprecated '%@' property for '%s'. Use '%@' instead.", alias, type, key);
  ((NSMutableDictionary *)json)[key] = number;
  }