utils/ssh: Load host keys only if strict_host_check is true

Loading host keys breaks setting up SSH connection (paramiko throws
BadHostKeyException exception) if issuer does not want/need strict key
matching.

One use case for ignoring strict_host_check is automating virtual guests
(i.e., over QEMU). Issuer may want to skip loading host keys and start
with a blank list of known host keys for sure.

Signed-off-by: Metin Kaya <metin.kaya@arm.com>

devlib/utils/ssh.py

@@ -397,6 +397,7 @@ class SshConnection(SshConnectionBase):
 
         with _handle_paramiko_exceptions():
             client = SSHClient()
+            if self.strict_host_check:
                 client.load_system_host_keys()
             client.set_missing_host_key_policy(policy)
             client.connect(