worked as lock_server and result_server，only support concurrent job <5 #47
Description
I follows README.rst to setup my paddles server,when 5 teuthology-worker was started,one job connect will be reset,the log print as follows：
2014-11-21T22:50:34.281 INFO:teuthology.run:Found tasks at /root/src/ceph-qa-suite-master/tasks
2014-11-21T22:50:34.282 INFO:teuthology.run_tasks:Running task internal.lock_machines...
2014-11-21T22:50:34.282 INFO:teuthology.task.internal:Locking machines...
2014-11-21T22:51:24.961 DEBUG:teuthology.lock:lock_many request: {'count': 2, 'os_type': 'centos', 'locked_by': 'scheduled_root@teuth.novalocal', 'description': '/var/www/html/teuthology2/root-2014-11-21_15:59:07-rgw-master-distro-basic-plana/10', 'machine_type': 'plana'}
2014-11-21T22:53:08.189 ERROR:teuthology.run_tasks:Saw exception from tasks.
Traceback (most recent call last):
File "/root/src/teuthology-master/virtualenv/lib/python2.7/site-packages/teuthology-0.1.0-py2.7.egg/teuthology/run_tasks.py", line 55, in run_tasks
manager.enter()
File "/root/.pyenv/versions/2.7.8/lib/python2.7/contextlib.py", line 17, in enter
return self.gen.next()
File "/root/src/teuthology-master/virtualenv/lib/python2.7/site-packages/teuthology-0.1.0-py2.7.egg/teuthology/task/internal.py", line 105, in lock_machines
ctx.archive, os_type, os_version, arch)
File "/root/src/teuthology-master/virtualenv/lib/python2.7/site-packages/teuthology-0.1.0-py2.7.egg/teuthology/lock.py", line 357, in lock_many
headers={'content-type': 'application/json'},
File "/root/src/teuthology-master/virtualenv/lib/python2.7/site-packages/requests/api.py", line 94, in post
return request('post', url, data=data, json=json, *_kwargs)
File "/root/src/teuthology-master/virtualenv/lib/python2.7/site-packages/requests/api.py", line 49, in request
return session.request(method=method, url=url, *_kwargs)
File "/root/src/teuthology-master/virtualenv/lib/python2.7/site-packages/requests/sessions.py", line 457, in request
resp = self.send(prep, *_send_kwargs)
File "/root/src/teuthology-master/virtualenv/lib/python2.7/site-packages/requests/sessions.py", line 569, in send
r = adapter.send(request, *_kwargs)
File "/root/src/teuthology-master/virtualenv/lib/python2.7/site-packages/requests/adapters.py", line 407, in send
raise ConnectionError(err, request=request)
ConnectionError: ('Connection aborted.', error(104, 'Connection reset by peer'))