doc: add doc for easy commit sign-off with -s

[sworleys]

Add some doc to let developers know about the -s flag
with git commit.

We were seeing some people writing the sign-off manually.

Signed-off-by: Stephen Worley sworley@cumulusnetworks.com

[mjstapp]

Approving too - I'll merge when CI finishes

[LabN-CI]

💚 Basic BGPD CI results: SUCCESS, 0 tests failed

Results table

_	_
Result	SUCCESS git merge/5471 118cf7e
Date	12/04/2019
Start	11:55:18
Finish	12:20:58
Run-Time	25:40
Total	1815
Pass	1815
Fail	0
Valgrind-Errors	0
Valgrind-Loss	0
Details	vncregress-2019-12-04-11:55:18.txt
Log	autoscript-2019-12-04-11:56:07.log.bz2
Memory	418 426 360

For details, please contact louberger

[NetDEF-CI]

Continuous Integration Result: SUCCESSFUL

Congratulations, this patch passed basic tests

Tested-by: NetDEF / OpenSourceRouting.org CI System

CI System Testrun URL: https://ci1.netdef.org/browse/FRR-FRRPULLREQ-9940/

This is a comment from an automated CI system.
For questions and feedback in regards to this CI system, please feel free to email
Martin Winter - mwinter (at) opensourcerouting.org.

Warnings Generated during build:

Debian 10 amd64 build: Successful with additional warnings

Debian Package lintian failed for Debian 10 amd64 build:
(see full package build log at https://ci1.netdef.org/browse/FRR-FRRPULLREQ-9940/artifact/DEB10BUILD/ErrorLog/log_lintian.txt)

W: frr source: pkg-js-tools-test-is-missing
W: frr source: pkg-js-tools-test-is-missing
W: frr-rpki-rtrlib: changelog-file-missing-explicit-entry 6.0-2 -> 7.3-dev-20191204-08-g118cf7edb-0 (missing) -> 7.3-dev-20191204-08-g118cf7edb-0~deb10u1
W: frr-pythontools: changelog-file-missing-explicit-entry 6.0-2 -> 7.3-dev-20191204-08-g118cf7edb-0 (missing) -> 7.3-dev-20191204-08-g118cf7edb-0~deb10u1
W: frr-snmp: changelog-file-missing-explicit-entry 6.0-2 -> 7.3-dev-20191204-08-g118cf7edb-0 (missing) -> 7.3-dev-20191204-08-g118cf7edb-0~deb10u1
W: frr-doc: changelog-file-missing-explicit-entry 6.0-2 -> 7.3-dev-20191204-08-g118cf7edb-0 (missing) -> 7.3-dev-20191204-08-g118cf7edb-0~deb10u1
W: frr: changelog-file-missing-explicit-entry 6.0-2 -> 7.3-dev-20191204-08-g118cf7edb-0 (missing) -> 7.3-dev-20191204-08-g118cf7edb-0~deb10u1
W: frr: spelling-error-in-readme-debian explecitly explicitly

---

CLANG Static Analyzer Summary

• Github Pull Request 5471, comparing to Git base SHA 86637de
• Base image data for Git 86637de does not exist - compare skipped

1 Static Analyzer issues remaining.

See details at
https://ci1.netdef.org/browse/FRR-FRRPULLREQ-9940/artifact/shared/static_analysis/index.html