sdp_parse.c: make z= timezone parsing more relaxed
sdp_parse.c: make z= timezone parsing more relaxed

Accept upper-case modifiers (DHMS) like parsing r= does.

Silence MeeGo Coverity issues CID#7578, CID#7577, CID#7576, CID#7575.

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