cros_vm_lib: Allow custom private key for ssh_ping

Since CL:286935, test ssh keys can be generated at build time, instead of
copying the static 'testing_rsa'. cros_vm_lib, especially its call to
'ssh_ping', needs to be extended to take a private key as an argument.

TEST=Trybot run with rambi-pre-cq, and a trybot run with a build that has the
USE flag 'generated_key' enabled, i.e., a generated private key instead of the
default key will be used for ssh.

Change-Id: I04e60367f9799d02877377e39ad675af358322c4
Commit-Ready: Daniel Wang <>
Tested-by: Daniel Wang <>
Reviewed-by: Simran Basi <>
1 file changed