test: handle very short tests that exit before reaching runlevel 2

Bootstrap-only tests that just verify basic functionality are often very
short.  This change handles that by retrying SIGUSR2 until Finit has had
the chance to finalize bootstrap and enable signals.

Signed-off-by: Joachim Wiberg <troglobit@gmail.com>

test/lib/setup.sh

@@ -226,7 +226,8 @@ wdstart()
 
 wdkill()
 {
-	kill -KILL $wdpid
+    say "Stopping test watchdog, pid $wdpid"
+    kill -KILL $wdpid
 }
 
 teardown()
@@ -247,11 +248,15 @@ teardown()
 		log "$fg_red" 'TEST FAIL' ''
 	fi
 
-	say "Telling Finit to shut down (set -$-) ..."
 	set +e
-	if [ -n "${finit_pid+x}" ]; then
-		texec kill -SIGUSR2 1
-	fi
+	say "Telling Finit to shut down (set -$-) ..."
+	while [ -n "${finit_pid+x}" ]; do
+	    if ! kill -USR2 "${finit_pid}" 2>/dev/null; then
+		break
+	    fi
+	    say "Retrying shutdown ..."
+	    sleep 1
+	done
 
 	say "Waiting for Finit to shut down ..."
 	wait