libstore: make Worker::removeGoal private

Change-Id: I8583d9ff752f702a10ec52b0330b0d4d4d2614fa

src/libstore/build/worker.hh

@@ -153,6 +153,11 @@ private:
      */
     void waitForInput();
 
+    /**
+     * Remove a dead goal.
+     */
+    void removeGoal(GoalPtr goal);
+
 public:
 
     const Activity act;
@@ -224,11 +229,6 @@ public:
      */
     GoalPtr makeGoal(const DerivedPath & req, BuildMode buildMode = bmNormal);
 
-    /**
-     * Remove a dead goal.
-     */
-    void removeGoal(GoalPtr goal);
-
     /**
      * Return the number of local build processes currently running (but not
      * remote builds via the build hook).