Fix docker daemon failed to set IPv6 gateway

This commit sets "net.ipv6.conf.eth0.accept_ra" to 0 to avoid the
file exists error.
refer to: https://github.com/moby/libnetwork/issues/2455

Change-Id: Ib0d7cec54bc79b3e29a95c298435b007e769e565

releasenotes/notes/fix-ipv6-route-exists-a62960bc329ca535.yaml

@@ -0,0 +1,6 @@
+---
+fixes:
+  - |
+    Fix a bug where docker daemon occasionally returns error:
+    failed to set IPv6 gateway while updating gateway when network_isolation
+    is enabled.

trove/guestagent/utils/docker.py

@@ -82,6 +82,8 @@ def _create_container_with_low_level_api(image: str, param: dict) -> None:
         host_config_kwargs["privileged"] = param.get("privileged")
     if param.get("volumes"):
         host_config_kwargs["binds"] = param.get("volumes")
+    if param.get("sysctls"):
+        host_config_kwargs["sysctls"] = param.get("sysctls")
     host_config = client.create_host_config(**host_config_kwargs)
 
     network_config_kwargs = dict()
@@ -161,6 +163,8 @@ def start_container(client, image, name="database",
     if network_mode == constants.DOCKER_HOST_NIC_MODE:
         create_network(client, constants.DOCKER_NETWORK_NAME)
         kwargs["network"] = constants.DOCKER_NETWORK_NAME
+        # eth0 is the nic name in the database container.
+        kwargs['sysctls'] = {"net.ipv6.conf.eth0.accept_ra": 0}
         return _create_container_with_low_level_api(image, kwargs)
     else:
         kwargs["network_mode"] = network_mode