Drop nonexistent shell.te policy from BOARD_SEPOLICY_UNION

Change-Id: Ib67e70ad04780f089116b8895e7683359d2b916f
Signed-off-by: rpcraig <rpcraig@tycho.ncsc.mil>
diff --git a/BoardConfigCommon.mk b/BoardConfigCommon.mk
index 56a9f15..57c0607 100644
--- a/BoardConfigCommon.mk
+++ b/BoardConfigCommon.mk
@@ -96,7 +96,6 @@
         mediaserver.te \
         rild.te \
         sensors_config.te \
-        shell.te \
         surfaceflinger.te \
         system_app.te \
         system_server.te \