Use GPtrArray for Jingle relay info

  This is already used for relay info in the FarStream backend, so is probably the right change to make there.
Fix possible leak when creating FarStream stream

  The relay info is created before some early returns, but without being freed there. It can be created within a condition where it's really needed instead. Then telling the GValue to take it means we don't need to free it ourselves.

Compile only.