cbuildbot: move GetTargetChromiteApiVersion out of cros_build_lib

The only user of GetTargetChromiteApiVersion is cbuildbot, so move it
out of cros_build_lib and into the cbuildbot/ tree.

BUG=chromium:868820
TEST=unittests pass

Change-Id: Ibfcb4ae2df6f82ca3e79f9a1ce2ceacc21d2ce8a
Reviewed-on: https://chromium-review.googlesource.com/c/chromiumos/chromite/+/1811323
Reviewed-by: Sean Abraham <seanabraham@chromium.org>
Commit-Queue: Mike Frysinger <vapier@chromium.org>
Tested-by: Mike Frysinger <vapier@chromium.org>
diff --git a/scripts/cbuildbot_launch_unittest.py b/scripts/cbuildbot_launch_unittest.py
index bef0991..db3faf9 100644
--- a/scripts/cbuildbot_launch_unittest.py
+++ b/scripts/cbuildbot_launch_unittest.py
@@ -12,10 +12,10 @@
 
 import mock
 
+from chromite.cbuildbot import commands
 from chromite.cbuildbot import repository
 from chromite.lib import build_summary
 from chromite.lib import constants
-from chromite.lib import cros_build_lib
 from chromite.lib import cros_sdk_lib
 from chromite.lib import cros_test_lib
 from chromite.lib import osutils
@@ -105,7 +105,7 @@
   def verifyCbuildbot(self, args, expected_cmd, version):
     """Ensure we invoke cbuildbot correctly."""
     self.PatchObject(
-        cros_build_lib, 'GetTargetChromiteApiVersion', autospec=True,
+        commands, 'GetTargetChromiteApiVersion', autospec=True,
         return_value=version)
 
     cbuildbot_launch.Cbuildbot('/cbuildbot_buildroot', '/depot_tools', args)
@@ -139,7 +139,7 @@
   def testMainMin(self):
     """Test a minimal set of command line options."""
     self.PatchObject(osutils, 'SafeMakedirs', autospec=True)
-    self.PatchObject(cros_build_lib, 'GetTargetChromiteApiVersion',
+    self.PatchObject(commands, 'GetTargetChromiteApiVersion',
                      autospec=True, return_value=(constants.REEXEC_API_MAJOR,
                                                   constants.REEXEC_API_MINOR))
     mock_repo = mock.MagicMock()
@@ -207,7 +207,7 @@
   def testMainMax(self):
     """Test a larger set of command line options."""
     self.PatchObject(osutils, 'SafeMakedirs', autospec=True)
-    self.PatchObject(cros_build_lib, 'GetTargetChromiteApiVersion',
+    self.PatchObject(commands, 'GetTargetChromiteApiVersion',
                      autospec=True, return_value=(constants.REEXEC_API_MAJOR,
                                                   constants.REEXEC_API_MINOR))
     mock_repo = mock.MagicMock()