cros_sdk: Drop --use-image support

We've phased out all users (deprecation notice for a while), and
builders are all passing no_use_image=False into the API.

BUG=b:266878468
TEST=./run_tests \
       service/sdk_unittest.py \
       api/controller/sdk_unittest.py \
       scripts/cros_sdk_unittest.py

Change-Id: I0920b0b5233a029dc6928ccafe9b488e76b9303a
Reviewed-on: https://chromium-review.googlesource.com/c/chromiumos/chromite/+/4304878
Commit-Queue: Brian Norris <briannorris@chromium.org>
Reviewed-by: Mike Frysinger <vapier@chromium.org>
Tested-by: Brian Norris <briannorris@chromium.org>
diff --git a/api/controller/sdk_unittest.py b/api/controller/sdk_unittest.py
index e3cc5b1..5cf8489 100644
--- a/api/controller/sdk_unittest.py
+++ b/api/controller/sdk_unittest.py
@@ -33,7 +33,6 @@
         self,
         no_replace=False,
         bootstrap=False,
-        no_use_image=False,
         cache_path=None,
         chroot_path=None,
         sdk_version=None,
@@ -43,7 +42,6 @@
         request = sdk_pb2.CreateRequest()
         request.flags.no_replace = no_replace
         request.flags.bootstrap = bootstrap
-        request.flags.no_use_image = no_use_image
 
         if cache_path:
             request.chroot.cache_dir = cache_path
@@ -95,13 +93,13 @@
         # Flag translation tests.
         # Test all false values in the message.
         request = self._GetRequest(
-            no_replace=False, bootstrap=False, no_use_image=False
+            no_replace=False,
+            bootstrap=False,
         )
         sdk_controller.Create(request, self.response, self.api_config)
         args_patch.assert_called_with(
             replace=True,
             bootstrap=False,
-            use_image=True,
             chroot_path=mock.ANY,
             cache_dir=mock.ANY,
             sdk_version=mock.ANY,
@@ -118,7 +116,6 @@
         request = self._GetRequest(
             no_replace=True,
             bootstrap=True,
-            no_use_image=True,
             sdk_version="foo",
             skip_chroot_upgrade=True,
         )
@@ -126,7 +123,6 @@
         args_patch.assert_called_with(
             replace=False,
             bootstrap=True,
-            use_image=False,
             chroot_path=mock.ANY,
             cache_dir=mock.ANY,
             sdk_version="foo",