add SUPERUSER_PACKAGE_PREFIX in prep for switch to new superuser

Change-Id: I0b880a6d0f9cf36c0a8419ec00fc978245adbb6f
diff --git a/config/common.mk b/config/common.mk
index 4a79c93..24ecb2b 100644
--- a/config/common.mk
+++ b/config/common.mk
@@ -1,6 +1,7 @@
 PRODUCT_BRAND ?= cyanogenmod
 
 SUPERUSER_EMBEDDED := true
+SUPERUSER_PACKAGE_PREFIX := com.android.settings.cyanogenmod.superuser
 
 # To deal with CM9 specifications
 # TODO: remove once all devices have been switched