CM-SDK: add PREDISMISSED_STATE constant required by CM13 DeskClock

See http://review.cyanogenmod.org/#/c/125484 which brings the
changes to allow third party components to set and modify alarms,
and which actually makes use of the ClockContract in the SDK. This
flushes out the fact that the ClockContract in CM13 added a new
state.

Change-Id: If6d57727298c0a749055337809b9a66e91078a01

src/java/cyanogenmod/alarmclock/ClockContract.java

@@ -227,6 +227,11 @@ public final class ClockContract {
          */
         public static final int DISMISSED_STATE = 7;
 
+        /**
+         * Alarm state when alarm has been dismissed before its intended firing time.
+         */
+        public static final int PREDISMISSED_STATE = 8;
+
         /**
          * Alarm year.
          *