Catch socket.gaierror and socket.error in sshKeyDist.py.

Discovered this one while debugging the key distribution utility:

    Traceback (most recent call last):
      File "/usr/lib/python2.6/threading.py", line 532, in __bootstrap_inner
        self.run()
      File "/home/carlo/keydist-utility/sshKeyDist.py", line 496, in run
        sshClient.connect(hostname=self.keydistObject.host,username=self.keydistObject.username,password=self.keydistObject.password,allow_agent=False,look_for_keys=False)
      File "/usr/local/lib/python2.6/dist-packages/ssh-1.8.0-py2.6.egg/ssh/client.py", line 283, in connect
        for (family, socktype, proto, canonname, sockaddr) in socket.getaddrinfo(hostname, port, socket.AF_UNSPEC, socket.SOCK_STREAM):
    gaierror: [Errno -2] Name or service not known