Update ensure_byte_buf_has_allocated_buffer_member to include primary allocation

[adpaco-aws]

Update ensure_byte_buf_has_allocated_buffer_member to include primary allocation so that the code

struct aws_byte_buf *buf1 = malloc(sizeof(*buf1));

ensure_byte_buf_has_allocated_buffer_member(buf1);

can be replaced by

struct aws_byte_buf *buf1 = ensure_byte_buf_has_allocated_buffer_member(buf1);

[jmklix]

Has this been added with the merged PR?

[adpaco-aws]

Hi @jmklix , which PR are you referring to? The issue comes from this comment and I believe it's still pending.