Use user-ID instead of usernames for container runs in tests

When running in kubedock, the tests failed because kubedock
can't work with the username when starting the container, but
expects the User-ID, which works for other docker APIs as
well.

Change-Id: I60e14e29fa06e81c16b0f5245b46e1ec9530a19b

tests/container-images/conftest.py

diff --git a/tests/container-images/conftest.py b/tests/container-images/conftest.py
index 8a4b8f2..3135180 100644
--- a/tests/container-images/conftest.py
+++ b/tests/container-images/conftest.py
@@ -55,7 +55,7 @@
     def start(self):
         self.container = self.docker_client.containers.run(
             image=self.image.id,
-            user="gerrit",
+            user="1000",
             volumes=self._define_volume_mounts(),
             ports={8080: str(self.port)},
             network=self.docker_network.name,
@@ -87,7 +87,7 @@
             image=image.id,
             entrypoint="/bin/ash",
             command=["-c", "tail -f /dev/null"],
-            user="gerrit",
+            user="1000",
             detach=True,
             auto_remove=True,
             platform="linux/amd64",

tests/container-images/gerrit-init/test_container_integration_gerrit_init.py

diff --git a/tests/container-images/gerrit-init/test_container_integration_gerrit_init.py b/tests/container-images/gerrit-init/test_container_integration_gerrit_init.py
index 0670002..85f49af 100644
--- a/tests/container-images/gerrit-init/test_container_integration_gerrit_init.py
+++ b/tests/container-images/gerrit-init/test_container_integration_gerrit_init.py
@@ -28,7 +28,7 @@
     tmp_site_dir = tmp_path_factory.mktemp("gerrit_site")
     container_run = docker_client.containers.run(
         image=gerrit_init_image.id,
-        user="gerrit",
+        user="1000",
         volumes={tmp_site_dir: {"bind": "/var/gerrit", "mode": "rw"}},
         detach=True,
         auto_remove=True,
@@ -64,7 +64,7 @@
         image=gerrit_init_image.id,
         entrypoint="/bin/ash",
         command=["-c", "tail -f /dev/null"],
-        user="gerrit",
+        user="1000",
         volumes={
             tmp_site_dir: {"bind": "/var/gerrit", "mode": "rw"},
             init_config_dir: {"bind": "/var/config", "mode": "rw"},

tests/container-images/gerrit-init/test_container_integration_gerrit_init_reindexing.py

diff --git a/tests/container-images/gerrit-init/test_container_integration_gerrit_init_reindexing.py b/tests/container-images/gerrit-init/test_container_integration_gerrit_init_reindexing.py
index 08e355e..7d60118 100644
--- a/tests/container-images/gerrit-init/test_container_integration_gerrit_init_reindexing.py
+++ b/tests/container-images/gerrit-init/test_container_integration_gerrit_init_reindexing.py
@@ -31,7 +31,7 @@
         entrypoint="/bin/ash",
         command=["-c", "tail -f /dev/null"],
         volumes={str(temp_site): {"bind": "/var/gerrit", "mode": "rw"}},
-        user="gerrit",
+        user="1000",
         detach=True,
         auto_remove=True,
         platform="linux/amd64",