refactor!: drop the _docker_bin override

napalm-linux 0.3.0 drops the Docker CLI methods the override served.
_container_engine_binary("docker") returns Container Station's path
itself, which is all netOrk needs: it reaches the engine through
open_container_engine (NetOrk/netork#765, phase 9).

Requires napalm-linux >= 0.3.0. Version 0.3.0.

tests/test_qnap_qts.py

@@ -97,7 +97,7 @@ class TestRolesDoNotShadowLinux:
     collision. There is nothing left to collide with.
     """
 
-    @pytest.mark.parametrize("method", ["get_services", "get_users", "get_docker_info"])
+    @pytest.mark.parametrize("method", ["get_services", "get_users"])
     def test_os_surface_resolves_to_linux(self, method):
         """QTS really is Linux for these, so inheriting them is correct."""
         from napalm_linux.linux import LinuxDriver
@@ -179,9 +179,10 @@ class TestDockerBinDiscovery:
         with patch.object(driver, "_send", return_value=""):
             assert driver._discover_docker_path() == "docker"
 
-    def test_docker_bin_hook_returns_the_discovered_path(self, driver):
-        driver._docker_path = "/opt/docker"
-        assert driver._docker_bin() == "/opt/docker"
+    def test_the_old_docker_methods_are_gone(self):
+        """netOrk reaches Container Station over the Engine API (NetOrk/netork#765)."""
+        for name in ("get_docker_info", "get_docker_outdated", "_docker_bin"):
+            assert not hasattr(QnapQtsDriver, name), name
 
 
 class TestContainerEngineBinary: