wait-for-emulator: skip adb log messages

Otherwise, we'd interpret this as "booting", which is wrong:

     $ adb -e shell getprop init.svc.bootanim
    * daemon not running. starting it now on port 5037 *
    * daemon started successfully *
    error: no devices found

tools/wait-for-emulator

@@ -24,7 +24,7 @@ while true; do
 	if [[ $sec -ge $timeout ]]; then
 		err "Timeout ($timeout seconds) reached - Failed to start emulator"
 	fi
-	out=$(adb -e shell getprop init.svc.bootanim 2>&1)
+	out=$(adb -e shell getprop init.svc.bootanim 2>&1 | grep -v '^\*')
 	if [[ "$out" =~ "command not found" ]]; then
 		err "$out"
 	fi