Possible memory corruption or vec misbehavior in metadata

[graydon]

In the metadata encoder, in the code that writes a metadata version constant at the end of metadata::encode:::encode_metadata, we wind up having to use a string literal rather than a vector constant. Somehow memory is getting modified under-foot, or something. Investigate. Not cool.

[pnkfelix]

I trust that Graydon will investigate this as time permits, but not for 0.6 release. De-milestoning.

[graydon]

Not sure what it was, but it works now.