autotest: push/pop a "test" profile for WiFi tests

Replace the recording of profile entries on test start / delete on exit by
creating a "test" profile that is pushed and poped.

BUG=chromium-os:12948
TEST=run matfunc; use list-profiles to verify the test profile is pushed; check the default profile at the end to verify no test services are present

Review URL: http://codereview.chromium.org/6723006

Change-Id: I54d88dbd55a387d902c53acc4639530edbdd87c1
1 file changed