Fixed an ImportError exception when loading localtunneld

ubuntu@server:~/talkain$ localtunneld
Traceback (most recent call last):
  File "/usr/local/bin/localtunneld", line 9, in <module>
    load_entry_point('localtunnel==0.6.1', 'console_scripts', 'localtunneld')()
  File "/usr/lib/python2.7/dist-packages/pkg_resources.py", line 337, in load_entry_point
    return get_distribution(dist).load_entry_point(group, name)
  File "/usr/lib/python2.7/dist-packages/pkg_resources.py", line 2279, in load_entry_point
    return ep.load()
  File "/usr/lib/python2.7/dist-packages/pkg_resources.py", line 1989, in load
    entry = __import__(self.module_name, globals(),globals(), ['__name__'])
  File "/usr/local/lib/python2.7/dist-packages/localtunnel/server/cli.py", line 9, in <module>
    from localtunnel.server.tunnel import Tunnel
  File "/usr/local/lib/python2.7/dist-packages/localtunnel/server/tunnel.py", line 11, in <module>
    from localtunnel.server import metrics
  File "/usr/local/lib/python2.7/dist-packages/localtunnel/server/metrics.py", line 6, in <module>
    from yunomi import dump_metrics
ImportError: No module named yunomi

Signed-off-by: Tal Kain <tal.kain@ravellosystems.com>