Remove redundant BOARD_SEPOLICY_UNION

BOARD_SEPOLICY_UNION is no longer required - all files found in
BOARD_SEPOLICY_DIRS are implicitly unioned.

FPIIM-1306

Change-Id: Ide813be902ee2b08a5f1b0a413816002a44dd9d9
diff --git a/Android.mk b/Android.mk
index cdbe311..4ade363 100755
--- a/Android.mk
+++ b/Android.mk
@@ -1,7 +1,3 @@
 # Fairphone specific SELinux policy variable definitions
 BOARD_SEPOLICY_DIRS += \
        device/fairphone_devices/sepolicy 
-
-BOARD_SEPOLICY_UNION += \
-       file_contexts \
-       su.te