#80 Confusing feedback for "invalid" ip entry in cache file

[Kalle Richter]

After failure of update with web mechanism for unknown reason manual invokation of ddclient result in output

WARNING:  file /var/cache/ddclient/ddclient.cache, line 3: Invalid Value for keyword 'ip' = ''
WARNING:  skipping update of richtercloud.de from <nothing> to 94.223.90.231.
WARNING:   last updated <never> but last attempt on Sun Feb 28 04:30:44 2016 failed.
WARNING:   Wait at least 5 minutes between update attempts.

where /var/cache/ddclient/ddclient.cache contains

## ddclient-3.8.2
## last updated at Sun Feb 28 04:36:32 2016 (1456630592)
atime=1456630592,backupmx=0,custom=0,host=richtercloud.de,ip=,mtime=0,mx=richtercloud.de,script=/nic/update,static=0,status=noconnect,warned-min-error-interval=0,warned-min-interval=0,wildcard=0,wtime=0 richtercloud.de

It's unclear whether this is a programming error since the cache appears to be incapable of handling failure (because those make it get into an unhandable state). In case it isn't the feedback should be improved in advise and logic.

experienced with 3.8.2-2ubuntu1