When the path of public key file contains "%", kitchen-sync fails with "ssh_percent_expand: unknown key %2"

[trombik]

When the path of public key file contains "%", such as "release%2F1.0.0," kitchen-sync fails with a cryptic error:

Fssh_percent_expand: unknown key %2
rsync: connection unexpectedly closed (0 bytes received so far) [sender]
rsync error: error in rsync protocol data stream (code 12) at io.c(226) [sender=3.1.2]
D Cleaning up local sandbox in /tmp/default-openbsd-59-amd64-sandbox-20161004-32285-1n5an6e
>>>>>> ------Exception-------
>>>>>> Class: Kitchen::ActionFailed
>>>>>> Message: Failed to complete #converge action: [malformed format string - %F]
>>>>>> ----------------------
>>>>>> Please see .kitchen/logs/kitchen.log for more details
>>>>>> Also try running `kitchen diagnose --all` for configuration
D ------Exception-------
D Class: Kitchen::ActionFailed
D Message: Failed to complete #converge action: [malformed format string - %F]
D ---Nested Exception---
D Class: ArgumentError
D Message: malformed format string - %F
D ------Backtrace-------

[trombik]

this happens because ssh(1) tries to expand "%" and fails.