Fixed typos in cassandra.ini

[arampaa]

Basics

Do not describe the purpose here but:

• Short descriptions should be in the release notes (added as entry in
  doc/news/_preparation_next_release.md which contains _(my name)_)
  Please always add something to the the release notes.
• Longer descriptions should be in documentation or in design decisions.
• Describe details of how you changed the code in commit messages
  (first line should have module: short statement syntax)
• References to issues, e.g. close #X, should be in the commit messages.

Checklist

Check relevant points but please do not remove entries.
For docu fixes, spell checking, and similar none of these points below
need to be checked.

• I added unit tests
• I ran all tests locally and everything went fine
• affected documentation is fixed
• I added code comments, logging, and assertions (see doc/CODING.md)
• meta data is updated (e.g. README.md of plugins)

Review

Remove the line below and add the "work in progress" label if you do
not want the PR to be reviewed:

"work in progress"

[markus2330]

Thank you for creating this PR! I added you to the private repo.

Please add yourself into the release notes as instructed by the build server (Syntax is wrong).

[markus2330]

@Piankero can you fix this PR please?

[sanssecours]

@arampaa Thank you for your contribution 💕. I added a slightly modified version of your changes to the master branch in PR #2818, since the Jenkins build job for this PR did not finish successfully, even after I restarted it multiple times.