sleep x seconds if no blocking queue was found

[razonyang]

QUEUE=* AND BLOCKING will crash workers sometimes, because there is no queue exists, when Resque_Job::reserveBlocking($emptyQueues, $timeout) was invoke, the following error will be shown:

PHP Fatal error: Uncaught CredisException: wrong number of arguments for 'blpop' command in /home/razon/Develop/Projects/php-resque/vendor/colinmollenhour/credis/Client.php:1167
Stack trace:
#0 /home/razon/Develop/Projects/php-resque/vendor/colinmollenhour/credis/Client.php(905): Credis_Client->read_reply('blpop')
#1 /home/razon/Develop/Projects/php-resque/lib/Resque/Redis.php(249): Credis_Client->__call('blpop', Array)
#2 /home/razon/Develop/Projects/php-resque/lib/Resque.php(178): Resque_Redis->__call('blpop', Array)
#3 /home/razon/Develop/Projects/php-resque/lib/Resque/Job.php(112): Resque::blpop(Array, 5)
#4 /home/razon/Develop/Projects/php-resque/lib/Resque/Worker.php(270): Resque_Job::reserveBlocking(Array, 5)
#5 /home/razon/Develop/Projects/php-resque/lib/Resque/Worker.php(165): Resque_Worker->reserve(true, 5)
#6 /home/razon/Develop/Projects/php-resque/bin/resque(109): Resque_Worker->work(5, true)
#7 {main}

Reproduce

1. FLUSHALL redis database - In order to clear the set prefix:queues.
2. EXEC BLOCKING=1 VERBOSE=1 COUNT=2 QUEUE=* bin/resque