Bug#775444: Issue warning if falling back to sha1

[jnqnfe <jnqnfe@gmail.com>]

Package: debootstrap
Tags: security patch

Patch attached to output warning if falling back to sha1.

commit 0911f1a8ba757a013e4c97e017634eb0ab746997
Author: jnqnfe <jnqnfe@gmail.com>
Date:   Thu Jan 15 19:22:17 2015 +0000

    Issue warning if having to fall back to sha1

diff --git a/debootstrap b/debootstrap
index 3d45c9c..c383517 100755
--- a/debootstrap
+++ b/debootstrap
@@ -461,6 +461,7 @@ if [ -z "$SHA_SIZE" ]; then
 	SHA_SIZE=256
 fi
 if ! in_path "sha${SHA_SIZE}sum" && ! in_path "sha${SHA_SIZE}"; then
+	warning SHA_SIZE "Cannot find binary for checking sha%s checksums, falling back to sha1" "${SHA_SIZE}"
 	SHA_SIZE=1
 fi
 DEBOOTSTRAP_CHECKSUM_FIELD="SHA$SHA_SIZE"