sdp: fix sessions compare
sdp: fix sessions compare

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