cut number of frames in lock screen demo animation from 15 to 8

This trims about 108k out of the settings app, and the animation is
still acceptable.

res/drawable/lock_anim.xml

@@ -19,19 +19,12 @@
 <animation-list
         xmlns:android="http://schemas.android.com/apk/res/android"
         android:oneshot="false">
-    <item android:drawable="@drawable/lock_anim_0" android:duration="200" />
-    <item android:drawable="@drawable/lock_anim_1" android:duration="200" />
-    <item android:drawable="@drawable/lock_anim_2" android:duration="200" />
-    <item android:drawable="@drawable/lock_anim_3" android:duration="200" />
-    <item android:drawable="@drawable/lock_anim_4" android:duration="200" />
-    <item android:drawable="@drawable/lock_anim_5" android:duration="200" />
-    <item android:drawable="@drawable/lock_anim_6" android:duration="200" />
-    <item android:drawable="@drawable/lock_anim_7" android:duration="200" />
-    <item android:drawable="@drawable/lock_anim_8" android:duration="200" />
-    <item android:drawable="@drawable/lock_anim_9" android:duration="200" />
-    <item android:drawable="@drawable/lock_anim_10" android:duration="200" />
-    <item android:drawable="@drawable/lock_anim_11" android:duration="200" />
-    <item android:drawable="@drawable/lock_anim_12" android:duration="200" />
-    <item android:drawable="@drawable/lock_anim_13" android:duration="200" />
-    <item android:drawable="@drawable/lock_anim_14" android:duration="200" />
+    <item android:drawable="@drawable/lock_anim_00" android:duration="400" />
+    <item android:drawable="@drawable/lock_anim_02" android:duration="400" />
+    <item android:drawable="@drawable/lock_anim_04" android:duration="400" />
+    <item android:drawable="@drawable/lock_anim_06" android:duration="400" />
+    <item android:drawable="@drawable/lock_anim_08" android:duration="400" />
+    <item android:drawable="@drawable/lock_anim_10" android:duration="400" />
+    <item android:drawable="@drawable/lock_anim_12" android:duration="400" />
+    <item android:drawable="@drawable/lock_anim_14" android:duration="400" />
 </animation-list>