[package] base-files: don't enter failsafe if triggered by switch

Fixes failsafe issues with switches after r38725.

Signed-off-by: Luka Perkov <luka@openwrt.org>

git-svn-id: svn://svn.openwrt.org/openwrt/trunk@38770 3c298f89-4303-0410-b956-a3cf2f4a3e73