init: set $PATH in second stage init

If the system partition has been updated and _PATH_DEFPATH has a new
value, then we must set $PATH in second stage init to take on the new
value, as well as having set it in first stage init.

Bug: 160210288
Test: build
Change-Id: I18765709dc9bff9379b0ae39272199cf74a79d2f
1 file changed