TpCallStreamEndpoint: ensure username/password is never NULL
TpCallStreamEndpoint: ensure username/password is never NULL

This is how it's done in TpBaseMediaCallStream as well.

Distrotech/telepathy-glib,Distrotech/telepathy-glib,Distrotech/telepathy-glib,Distrotech/telepathy-glib,Distrotech/telepathy-glib