Description:fix vsnprintf

Team:OTHERS
Feature or Bugfix:Bugfix
Binary Source:NA
PrivateCode(Yes/No):No

Change-Id: Ibf9200940137b8ae67e01bcc1ec1f6492a286fe3
Reviewed-on: http://mgit-tm.rnd.huawei.com/10617507Reviewed-by: Nliulei 00510663 <lewis.liulei@huawei.com>
Tested-by: Npublic jenkins <public_jenkins@notesmail.huawei.com>
Reviewed-by: Nshenwei 00579521 <denny.shenwei@huawei.com>