fixed bug where services would appear to start, but would actually still be stopped

Without setting pty=False, some services will print the standard start response:

    [servername] out: sudo password: * Starting web server apache2
    [servername] out:    ...done.

However, the service will not actually be restarted. Stopping appears to work without pty=False.

Tested with the apache2 service on Ubuntu 12.04.

See http://stackoverflow.com/questions/6379484/fabric-appears-to-start-apache2-but-doesnt for more info.