[46793255] return error if given an past expiration time

Signed-off-by: Henry Chen <hchen@vmware.com>
Merge pull request #12 from Henry-CF/bugfix

[46793255] return error if given a past expiration time
[Bug 46796967] fix bug

  invalid url error msg should disappear after input correct url
Merge pull request #13 from Chunjie/master

[Bug 46796967] fix bug
Merge remote branch 'vmw-tmpst/master'