Fix the bug of docker import command when import a image with a tag use format 'URL|- [REPOSITORY[:TAG]]'.Fixes #7714

Signed-off-by: Lei Jitang <leijitang@huawei.com>
add docker import test with a tag. Fixes #7714

Signed-off-by: Lei Jitang <leijitang@huawei.com>
Merge pull request #7716 from coolljt0725/master

Fix the bug of docker import command when import a image with a tag use format 'URL|- [REPOSITORY[:TAG]]'