qdist: fix memory leak during binning

In qdist_bin__internal(), to->entries is initialized to a 1-element array,
which we then leak when n == from->n. Fix it.

Signed-off-by: Emilio G. Cota <cota@braap.org>
Message-Id: <1469459025-23606-2-git-send-email-cota@braap.org>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
