Have the NetworkScoreService bind to the scorer.

If the current active scorer provides a service that can handle the
android.net.scoring.SCORE_NETWORKS action then the NetworkScoreService
will bind to that service to keep the scorer alive. If no service is
discovered then no attempt to bind will be made.

BUG: 27612145
Change-Id: I3f6ed0cbd83e658f1533c3e37b0cac2692c01761

services/java/com/android/server/SystemServer.java

@@ -1423,6 +1423,12 @@ public final class SystemServer {
                 } catch (Throwable e) {
                     reportWtf("Notifying MmsService running", e);
                 }
+
+                try {
+                    if (networkScoreF != null) networkScoreF.systemRunning();
+                } catch (Throwable e) {
+                    reportWtf("Notifying NetworkScoreService running", e);
+                }
                 Trace.traceEnd(Trace.TRACE_TAG_SYSTEM_SERVER);
             }
         });