Paiwei fix sandbox yield

make sure gearmand server is running before we yield in the test_admin.py

the way to check is to call 'ps ax' and check if 'gearmand -p [port]' string exists.

the loop terminates if the server is running or timeout

if there is a timeout, sandbox will yield a success=False flag which triggers the raise Exception in the test_admin.py

also makes sure that the process is killed if there is a timeout