"allow_in_call_touch_ui" config resource now defaults to true

Now that most devices *do* have prox sensors, it's clearest for this
resource to be true by default (and then overridden on a per-product
basis for those rare devices that can't use the onscreen in-call UI.)

(By the way, as of change https://android-git.corp.google.com/g/61135 in
gingerbread we no longer support *any* non-prox-sensor devices.  So this
resource is currently not overridden anywhere in our tree.)

Change-Id: Ice277bbfa70823aec5e49e31ca2ef17de0e5f010
diff --git a/res/values/config.xml b/res/values/config.xml
index 5c84336..0b821c4 100644
--- a/res/values/config.xml
+++ b/res/values/config.xml
@@ -48,7 +48,7 @@
          specific properties of the device, perhaps by detecting the
          presence of a proximity sensor and/or hard SEND/END keys.  (If
          so, we wouldn't need this flag at all.) -->
-    <bool name="allow_in_call_touch_ui">false</bool>
+    <bool name="allow_in_call_touch_ui">true</bool>
 
     <!-- OTA configuration values, used when provisioning CDMA devices.
          Following defaults values of zero means OTA UI is completely disabled.