DataWatch does not return node data if allow_missing_node enabled

[srwilson]

When DataWatch has allow_missing_node enabled, the data argument given to the callback is always None

Test program:

import kazoo.client

c = kazoo.client.KazooClient(<host>)
c.start()

c.create('/testnode', 'DATA')

@c.DataWatch('/testnode', allow_missing_node=True)                                                                                                                                                                                                                                                                           
def signal_update(data, stat):                                                                                                                                                                                                                                                                                                                                    
    print data, stat

c.set('/testnode', 'NEW_DATA')

Prints:

None ZnodeStat(czxid=8591709603, mzxid=8591709603, ctime=1355968927708, mtime=1355968927708, version=0, cversion=0, aversion=0, ephemeralOwner=0, dataLength=4, numChildren=0, pzxid=8591709603)
None ZnodeStat(czxid=8591709603, mzxid=8591709604, ctime=1355968927708, mtime=1355968927712, version=1, cversion=0, aversion=0, ephemeralOwner=0, dataLength=8, numChildren=0, pzxid=8591709603)

[diranged]

I'm looking forward to seeing this fixed as well... :)

[bbangert]

I've tested that this actually fixes the issue, the tests were also quite broke.