Using @hosts or @roles decorator meddle with fab -d taskname output

[shaftoe]

It's a small bug, but still...

alex~$ cat fabfile.py
from fabric.api import *

@task
@roles('fake_role')
def broken_task(my_argument=True):
'''Arguments is ok only if @roles is missing'''
local('Hello world!')

alex~$ fab -d broken_task
Displaying detailed information for task 'broken_task':

Arguments is ok only if @roles is missing
Arguments:

alex~$ sed -i '/fake_role/d' fabfile.py

alex~$ fab -d broken_task
Displaying detailed information for task 'broken_task':

Arguments is ok only if @roles is missing
Arguments: my_argument=True

[akitada]

This is a duplicate of #971