Build fails on generate_doc_index.sh in sandboxed env

[Filip Pytloun]

Because the script is referenced in path outside of debian source package.
Fortunately solution is pretty simple - include tool in package.

Full error:

# contrail-docs
# Index files
for file in /tmp/buildd/contrail-3.0+0~1455814590.3~1.a9bb944/usr/share/doc/contrail-docs/html/messages/*; do \
  /tmp/buildd/contrail-3.0+0~1455814590.3~1.a9bb944/tools/packages/utils/generate_doc_index.sh $file; \
 done
/bin/sh: 2: /tmp/buildd/contrail-3.0+0~1455814590.3~1.a9bb944/tools/packages/utils/generate_doc_index.sh: not found
/bin/sh: 2: /tmp/buildd/contrail-3.0+0~1455814590.3~1.a9bb944/tools/packages/utils/generate_doc_index.sh: not found
/bin/sh: 2: /tmp/buildd/contrail-3.0+0~1455814590.3~1.a9bb944/tools/packages/utils/generate_doc_index.sh: not found

[OpenContrail Admin (ci-admin-f)]

Review in progress for https://review.opencontrail.org/17437
Submitter: Filip Pytloun (<email address hidden>)

[OpenContrail Admin (ci-admin-f)]

Review in progress for https://review.opencontrail.org/23555
Submitter: Raj Reddy (<email address hidden>)

[OpenContrail Admin (ci-admin-f)]

Reviewed: https://review.opencontrail.org/23555
Committed: http://github.org/Juniper/contrail-packaging/commit/f6875d6e0a10ea053ca781d4f9a27d5d50e211bb
Submitter: Zuul
Branch: master

commit f6875d6e0a10ea053ca781d4f9a27d5d50e211bb
Author: Raj Reddy <email address hidden>
Date: Tue Aug 23 17:58:53 2016 -0700

The utils directory should be copied to debian directory for use in rules
scripts.

Change-Id: Icff53c8f94142472744ce7c52a06fc145bfbb54c
Partial-Bug: #1547494

[OpenContrail Admin (ci-admin-f)]

Reviewed: https://review.opencontrail.org/17437
Committed: http://github.org/Juniper/contrail-packages/commit/486f91cf77560070354354fa87ed2bfb132ef829
Submitter: Zuul
Branch: master

commit 486f91cf77560070354354fa87ed2bfb132ef829
Author: Filip Pytloun <email address hidden>
Date: Fri Feb 19 10:28:02 2016 +0100

Fix generate_doc_index.sh execution when running in sandboxed build

Closes-Bug: #1547494
Change-Id: Ic2c8ce352bfacab5144cc0d09e84e6e7d1233397