Only execute IdentityFetcher commands after start() has been called:
- Also delete the existing fetcher commands in start(), not in the constructor: To ensure that no duplicate fetches are done in the loop which starts fetching all identities at startup of WOT, we need to delete all existing fetch command en-bloc with the loop. Further, doing database stuff in constructors is ugly anyway.
- Fixes issue https://bugs.freenetproject.org/view.php?id=6004