This adds a check to the `#wait_for_reboot` method on the linux
guest reboot capability to determine if the a reboot is still
in process. This prevents the reboot process from being initiated
and the `#ready?` check on the guest being called before the
system shutdown process has shutdown the communicator process.
Keep the default duration as a constant and fetch the custom environment
variable at run time with a fallback to the default. Set the sleep duration
into a constant and add tests covering the expected behaviors when the
default duration is in use as well as the override value. Also match the
environment variable up with the constant just for consistency.
Previously the maximum amount of time Vagrant would poll for whether a
machine has successfully reboot was hard coded to 120 seconds. This
change introduces the VAGRANT_MAX_REBOOT_RETRY_TIMEOUT environment
variable to allow this attribute to be configurable.
Add RSpec tests of the maximum retry logic. Since the maximum retries
are configured as a constant, we'd need to reload the class and that's
fairly ugly to do in RSpec.
Fixes#11695
