The new wpa_supplicant configuration writing design (rename instead of
write to original file) did not fail with the symlink-to-self case, so
replace this with the config file being replaced with a directory. In
addition, get rid of unnecessary use of subprocess since run-tests.py is
running as root nowadays.
Signed-off-by: Jouni Malinen <jouni@qca.qualcomm.com>
