poll: Fix realloc in ssh_poll_ctx_resize().
poll: Fix realloc in ssh_poll_ctx_resize().

mwgoldsmith/ssh,mwgoldsmith/libssh,mwgoldsmith/libssh,mwgoldsmith/ssh,mwgoldsmith/libssh,mwgoldsmith/ssh,mwgoldsmith/ssh,mwgoldsmith/libssh