Changed default value of MSRP relay port to 0

Ignore-this: 287f9a2a76b5145adbf575f5e58d36d1

darcs-hash:20090320131615-1e3d8-4cb53b5b76d98ed0da6f8a3bbe14de770ef780a6
Fixed typo when instantiating Credentials

Ignore-this: 9e03e1398daa6a4e5dd5f7b65512b452

darcs-hash:20090320132313-1e3d8-a7bcef9e3b43ba010183b3e1385b5872fa194fb7