Move adbd to an apex.

Test: adb shell "su 0 readlink /proc/\`pidof adbd\`/exe"
Change-Id: I84dfe4d1b28b619f98c03a2c8eeef2c783d30af2
diff --git a/CleanSpec.mk b/CleanSpec.mk
index 73379cd..c84bd24 100644
--- a/CleanSpec.mk
+++ b/CleanSpec.mk
@@ -89,3 +89,4 @@
 $(call add-clean-step, rm -rf $(PRODUCT_OUT)/recovery/root/product_services)
 $(call add-clean-step, rm -rf $(PRODUCT_OUT)/debug_ramdisk/product_services)
 $(call add-clean-step, find $(PRODUCT_OUT) -type l -name "charger" -print0 | xargs -0 rm -f)
+$(call add-clean-step, rm -f $(PRODUCT_OUT)/system/bin/adbd)