no message
Merge branch 'master' of https://github.com/easemob/sdkexamples-ios

# By jifang1218 (1) and winterSleep (1)
# Via jifang1218
* 'master' of https://github.com/easemob/sdkexamples-ios:
  rename didMessageAttachmentsStatusChange to didMessageAttachmentsStatusChanged
  修改附件下载完成后的显示