Allow error output when checking redis-cli executable

Author: jsternberg

bin/check

@@ -31,7 +31,7 @@ dirs.each do |dir|
 end
 
 print "Testing redis-cli executable: "
-unless system(*config.redis_command, '--version', err: '/dev/null')
+unless system(*config.redis_command, '--version')
   abort "FAILED"
 end