nta.c: use random key when generating tags
nta.c: use random key when generating tags

Ignore-this: 3e989f42549acbdbc259383b1b64e74d

darcs-hash:20090323172250-db55f-602a6d7ebd4e850351ba610182b5cb8d99d5de67.gz

BelledonneCommunications/sofia-sip,jart/sofia-sip,erdincay/sofia-sip,xhook/sofia-sip,erdincay/sofia-sip,xhook/sofia-sip,xhook/sofia-sip,jart/sofia-sip,BelledonneCommunications/sofia-sip,BelledonneCommunications/sofia-sip,unispeech/sofia-sip,unispeech/sofia-sip,erdincay/sofia-sip,unispeech/sofia-sip,jart/sofia-sip,xhook/sofia-sip,unispeech/sofia-sip,xhook/sofia-sip,erdincay/sofia-sip,BelledonneCommunications/sofia-sip