atest: rename __get_hostnames

Change-Id: I6f58bb83be2682ae3c083df5a022094cf4cf41c8
Bug: chromium:1001153
Reviewed-on: https://chromium-review.googlesource.com/c/chromiumos/third_party/autotest/+/1788125
Reviewed-by: Gregory Nisbet <gregorynisbet@google.com>
Reviewed-by: Aviv Keshet <akeshet@chromium.org>
Commit-Queue: Gregory Nisbet <gregorynisbet@google.com>
Tested-by: Gregory Nisbet <gregorynisbet@google.com>
Auto-Submit: Gregory Nisbet <gregorynisbet@google.com>
diff --git a/cli/host.py b/cli/host.py
index cf7c170..50c59b1 100644
--- a/cli/host.py
+++ b/cli/host.py
@@ -1616,7 +1616,7 @@
         if self.hosts:
             hostnames = self.hosts
         else:
-            hostnames = self.__get_hostnames(
+            hostnames = self._host_skylab_migrate_get_hostnames(
                 model=self.model,
                 board=self.board,
                 pool=self.pool,