Remove setting codec list in sip_message.py

darcs-hash:20090423154616-58103-bf9c8c27b0515974d5304b09936a782da50ecd1e
session2: end streams when receive BYE

darcs-hash:20090424063102-b2873-324bfdac52233e7f40486e3a0a3910ddfd1bc785