- ssh_key_path is removed in all cases.
- The new fixer is not checking the builder type so it will execute for all
builders.
- If ssh_key_path exists without ssh_private_key_file then it will assign
the value of ssh_path_path to ssh_private_key_file
- If ssh_private_key_file and ssh_key_path exist, then ssh_key_path is
simply removed
I wanted to emit a warning messsage to the user but it didn't seem like
the ui.* interface was exposed to fixers.