Handle android branch/target/version for boards without android.

BUG=chromium:1015034
TEST=manual, run_tests

Change-Id: I83d15ab98fabf7bd1091745c1fbae117d96a40fc
Reviewed-on: https://chromium-review.googlesource.com/c/chromiumos/chromite/+/1865693
Reviewed-by: Alex Klein <saklein@chromium.org>
Tested-by: Michael Mortensen <mmortensen@google.com>
Commit-Queue: Michael Mortensen <mmortensen@google.com>
diff --git a/api/controller/packages.py b/api/controller/packages.py
index 0afec19..d5d58f0 100644
--- a/api/controller/packages.py
+++ b/api/controller/packages.py
@@ -119,12 +119,15 @@
 def GetTargetVersions(input_proto, output_proto, _config):
   """Returns the target versions."""
   build_target = controller_util.ParseBuildTarget(input_proto.build_target)
-  output_proto.android_version = packages.determine_android_version(
-      [build_target])
-  output_proto.android_branch_version = packages.determine_android_branch(
-      build_target)
-  output_proto.android_target_version = packages.determine_android_target(
-      build_target)
+  android_version = packages.determine_android_version([build_target])
+  if android_version:
+    output_proto.android_version = android_version
+  android_branch_version = packages.determine_android_branch(build_target)
+  if android_branch_version:
+    output_proto.android_branch_version = android_branch_version
+  android_target_version = packages.determine_android_target(build_target)
+  if android_target_version:
+    output_proto.android_target_version = android_target_version
   output_proto.chrome_version = packages.determine_chrome_version(build_target)
   # TODO(crbug.com/1004438): Implement remaining version fields.