Revert "generate_au_zip: Add unsquashfs, remove bsdiff and bspatch."

This reverts commit 9d29f568992107c0f537dc951a938c49190e305a.

Reason for revert: Need bspatch binary for PaygenBuild* stages.

Original change's description:
> generate_au_zip: Add unsquashfs, remove bsdiff and bspatch.
> 
> We no longer use bsdiff nor bspatch libraries to generate or apply payloads. We
> only use their shared library. This patch removes them from generate_au_zip.py.
> 
> Also we are adding squashfs update support for android container and we need our
> custom unsquashfs to generate the file map of the squashfs image. This patch
> adds it to generate_au_zip.py.
> 
> BUG=none
> TEST=submitted a tryjob
> 
> Change-Id: I027cb75321fbf26047e958a7aace90fe7afc3b4f
> Reviewed-on: https://chromium-review.googlesource.com/644151
> Commit-Ready: Amin Hassani <ahassani@chromium.org>
> Tested-by: Amin Hassani <ahassani@chromium.org>
> Reviewed-by: Dan Erat (OOO Fri-Mon) <derat@chromium.org>

BUG=761271

Change-Id: I4411630537d383cb3e9a88438d12a826bcdea070
Reviewed-on: https://chromium-review.googlesource.com/646812
Reviewed-by: Nicolas Boichat <drinkcat@chromium.org>
Commit-Queue: Nicolas Boichat <drinkcat@chromium.org>
Tested-by: Nicolas Boichat <drinkcat@chromium.org>
diff --git a/build_library/generate_au_zip.py b/build_library/generate_au_zip.py
index 24a1bdc..0cd72e0 100755
--- a/build_library/generate_au_zip.py
+++ b/build_library/generate_au_zip.py
@@ -27,8 +27,9 @@
     '/usr/bin/cgpt',
     '/usr/bin/delta_generator',
     '/usr/bin/simg2img',
-    # This version includes custom patches with bug fixes.
-    '/usr/bin/unsquashfs',
+    # These versions include custom patches with bug fixes.
+    '/usr/bin/bsdiff',
+    '/usr/bin/bspatch',
     ]
 EXECUTABLE_FILES = BINARY_EXECUTABLES + [
     '~/trunk/src/scripts/common.sh',