Fix double parsing on 32 bit devices. (#787)

Author: ryanwilson

Firebase/Database/Persistence/FLevelDBStorageEngine.m

@@ -687,7 +687,7 @@ - (id)fixDoubleParsing:(id)value {
                 NSString *doubleString = [value stringValue];
                 return [NSNumber numberWithDouble:[doubleString doubleValue]];
             } else {
-                return [NSNumber numberWithLong:[value longValue]];
+                return [NSNumber numberWithLongLong:[value longLongValue]];
             }
         }
     }