Make the .d file a mandatory output of the ObjcCompileAction.

--
MOS_MIGRATED_REVID=135495881

src/main/java/com/google/devtools/build/lib/rules/objc/ObjcCompileAction.java

diff --git a/src/main/java/com/google/devtools/build/lib/rules/objc/ObjcCompileAction.java b/src/main/java/com/google/devtools/build/lib/rules/objc/ObjcCompileAction.java
index 9a617f6..47c4ff1 100644
--- a/src/main/java/com/google/devtools/build/lib/rules/objc/ObjcCompileAction.java
+++ b/src/main/java/com/google/devtools/build/lib/rules/objc/ObjcCompileAction.java
@@ -124,6 +124,11 @@
   }
 
   @Override
+  public ImmutableSet<Artifact> getMandatoryOutputs() {
+    return ImmutableSet.of(dotdFile.artifact());
+  }
+
+  @Override
   public void execute(ActionExecutionContext actionExecutionContext)
       throws ActionExecutionException, InterruptedException {
     super.execute(actionExecutionContext);