ospf6d: fix argument processing in the "area ... range" command (backport #9108)

[mergify]

This is an automatic backport of pull request #9108 done by Mergify.
Cherry-pick of b9ff9be has failed:

On branch mergify/bp/stable/8.0/pr-9108
Your branch is ahead of 'origin/stable/8.0' by 1 commit.
  (use "git push" to publish your local commits)

You are currently cherry-picking commit b9ff9be45.
  (fix conflicts and run "git cherry-pick --continue")
  (use "git cherry-pick --skip" to skip this patch)
  (use "git cherry-pick --abort" to cancel the cherry-pick operation)

Unmerged paths:
  (use "git add <file>..." to mark resolution)
	both modified:   doc/user/ospf6d.rst

no changes added to commit (use "git add" and/or "git commit -a")

To fix up this pull request, you can check it out locally. See documentation: https://docs.github.com/en/github/collaborating-with-pull-requests/reviewing-changes-in-pull-requests/checking-out-pull-requests-locally

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[LabN-CI]

💚 Basic BGPD CI results: SUCCESS, 0 tests failed

Results table

_	_
Result	SUCCESS git merge/9296 92c61a3
Date	08/04/2021
Start	12:10:26
Finish	12:36:03
Run-Time	25:37
Total	1813
Pass	1813
Fail	0
Valgrind-Errors
Valgrind-Loss
Details	vncregress-2021-08-04-12:10:26.txt
Log	autoscript-2021-08-04-12:11:37.log.bz2
Memory	516 481 423

For details, please contact louberger

[NetDEF-CI]

Continuous Integration Result: SUCCESSFUL

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-20802/

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.

[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-20805/

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.