Fix #7843

When doing `docker start -a` on a container that won't start, terminal
was getting stuck on the attach, even after container removal.

Docker-DCO-1.1-Signed-off-by: Brian Goff <cpuguy83@gmail.com> (github: cpuguy83)
Merge pull request #8224 from cpuguy83/7843_fix_start_attach_error_hang

Fix #7843 start -a can cause frozen term