Ensure a resized empty buffer is null-terminated.
The new buffer code is using the pool, which ensures its buffers are null-terminated. However, if a "new" buffer from another part of the code were passed to one of the temporary interfaces that resizes the buffer, it's possible a non-terminated string might end up being passed through. It's reasonable to expect mutt_b2s() for a "new" buffer should be the same as after it is resized larger. So ensure the resulting buf->data is properly terminated to avoid surprises.
Showing with 2 additions and 0 deletions