DropBox logging of app & system server crashes.

The crashes are also reported to the event log (and of course the
main logcat, like they always have been).  Ordinary Log.e(t,m,e) isn't dropboxed
but there's a new Log.wtf() which always is.  (Still @pending in this change.)

Add a hook to IPowerManager to crash the system server on demand
(only for apps with REBOOT permission, since it's basically a restart).
This is not exposed in PowerManager, must be invoked directly -- mostly
this is there so "Bad Behavior" in dev tools can do it.
diff --git a/core/java/android/provider/Settings.java b/core/java/android/provider/Settings.java
index 947ab19..09651f1 100644
--- a/core/java/android/provider/Settings.java
+++ b/core/java/android/provider/Settings.java
@@ -3710,6 +3710,11 @@
                 "dropbox:";
 
         /**
+         * Nonzero causes Log.wtf() to crash.
+         */
+        public static final String WTF_IS_FATAL = "wtf_is_fatal";
+
+        /**
          * The length of time in milli-seconds that automatic small adjustments to
          * SystemClock are ignored if NITZ_UPDATE_DIFF is not exceeded.
          */