workspace_lib: Remove this library.

This library partially implemented the Chrome OS Brillo concept of a
workspace. That concept is no longer relevant, so remove the library.

Update assorted users, removing the concept of workspace where it seems
appropriate.

BUG=chromium:530677
TEST=run_tests

Change-Id: Icb43d24428f3c35e89e6c90325cbd03382670ffd
Reviewed-on: https://chromium-review.googlesource.com/305025
Commit-Ready: Don Garrett <dgarrett@chromium.org>
Tested-by: Don Garrett <dgarrett@chromium.org>
Reviewed-by: Don Garrett <dgarrett@chromium.org>
diff --git a/scripts/cros_unittest.py b/scripts/cros_unittest.py
index 7510fca..e05ef90 100644
--- a/scripts/cros_unittest.py
+++ b/scripts/cros_unittest.py
@@ -13,7 +13,7 @@
 from chromite.scripts import cros
 
 
-class RunScriptTest(cros_test_lib.WorkspaceTestCase):
+class RunScriptTest(cros_test_lib.MockTempDirTestCase):
   """Test the main functionality."""
 
   def setUp(self):