Fix usagestats DUMP OF SERVICE

DUMP OF SERVICE Usagestats was empty in bugreports
because an unexpected -a argument was being passed.
adb shell pm dump <package> had a similar issue with --packages

Change-Id: Ic67c723b8edc74ec7c9c48582b08896ca3430a4a
Fix: 70777338
Test: adb shell pm dump <package> and bugreports now contain usage stats

core/java/android/app/ActivityManager.java

@@ -3835,7 +3835,7 @@ public class ActivityManager {
         pw.println();
         dumpService(pw, fd, ProcessStats.SERVICE_NAME, new String[] { packageName });
         pw.println();
-        dumpService(pw, fd, "usagestats", new String[] { "--packages", packageName });
+        dumpService(pw, fd, "usagestats", new String[] { packageName });
         pw.println();
         dumpService(pw, fd, BatteryStats.SERVICE_NAME, new String[] { packageName });
         pw.flush();

services/usage/java/com/android/server/usage/UsageStatsService.java

@@ -492,8 +492,8 @@ public class UsageStatsService extends SystemService implements
                         flushToDiskLocked();
                         pw.println("Flushed stats to disk");
                         return;
-                    } else {
-                        // Anything else is a pkg to filter
+                    } else if (arg != null && !arg.startsWith("-")) {
+                        // Anything else that doesn't start with '-' is a pkg to filter
                         pkg = arg;
                         break;
                     }