finish build_target_lib.get_default_sysroot_path migration [reland]

This allows us to drop the build_target_lib import from cros_build_lib.

The failing platform2 code that caused this to revert before has been
fixed, and cs/ doesn't show any other latent hits.

BUG=chromium:1170007
TEST=CQ passes

Change-Id: I284d99fc2570eff7c4e843140efdfe5a56acc8d5
Reviewed-on: https://chromium-review.googlesource.com/c/chromiumos/chromite/+/2814898
Tested-by: Mike Frysinger <vapier@chromium.org>
Auto-Submit: Mike Frysinger <vapier@chromium.org>
Commit-Queue: Sergey Frolov <sfrolov@google.com>
Reviewed-by: Sergey Frolov <sfrolov@google.com>
diff --git a/cli/deploy_unittest.py b/cli/deploy_unittest.py
index 353d2ae..b78b53d 100644
--- a/cli/deploy_unittest.py
+++ b/cli/deploy_unittest.py
@@ -16,6 +16,7 @@
 
 from chromite.cli import command
 from chromite.cli import deploy
+from chromite.lib import build_target_lib
 from chromite.lib import cros_build_lib
 from chromite.lib import cros_test_lib
 from chromite.lib import remote_access
@@ -317,7 +318,8 @@
     self.PatchObject(
         remote_access, 'ChromiumOSDeviceHandler', return_value=self.device)
     self.PatchObject(cros_build_lib, 'GetBoard', return_value=None)
-    self.PatchObject(cros_build_lib, 'GetSysroot', return_value='sysroot')
+    self.PatchObject(build_target_lib, 'get_default_sysroot_path',
+                     return_value='sysroot')
     self.package_scanner = self.PatchObject(deploy, '_InstallPackageScanner')
     self.get_packages_paths = self.PatchObject(
         deploy, '_GetPackagesByCPV', side_effect=self.FakeGetPackagesByCPV)