Sanity checks for Kea 2.1.5 rc2

We are now at step SANITY CHECKS of Kea 2.1.5 rc2.

Please verify the packages and files according to "4. Sanity Checks" chapter on:
    https://wiki.isc.org/bin/view/QA/KeaReleaseProcess#4.%20Sanity%20Checks
and your imagination.
Before starting any checks, please state what check you are doing in a
thread/discussion (not as comment) in Sanity Checks issue in GitLab:
    None
When you finish given check state in the same thread/discussion what is the result.
This way we know what is covered upfront and we can avoid repeating ourselves.

Release content is located on:
1) [tarballs] repo.isc.org in the following folders:
   /data/shared/sweng/kea/releases/2.1.5-rc2
   /data/shared/sweng/kea/releases/premium-2.1.5-rc2
   /data/shared/sweng/kea/releases/subscription-2.1.5-rc2

SHA256 (kea-2.1.5.tar.gz) = e01263183bb6cb07567b87d8041a142a2f19d30cec000b66e3a49fad10c50194
SHA256 (kea-premium-2.1.5.tar.gz) = ba53267b0caf1cb92ae7b6e12edbdb4a33186d64a200f2b5ec503e038803f7bd
SHA256 (kea-subscription-2.1.5.tar.gz) = ac4c4a12cd6905a2901fe15e48cf890a18bbdb1d89651b3df6bf1e7cace0d471

2) APK, deb, RPM packages on packages.aws.isc.org, exact packages versions are stored here:
    https://jenkins.aws.isc.org/job/kea-dev/job/pkg/768/
    Release versions are:
    APK: 2.1.5-r20220426154040: https://packages.aws.isc.org/#browse/search/raw=format%3Draw%20AND%20name.raw%3D*r20220426154040.apk
    deb: 2.1.5-isc20220426154040: https://packages.aws.isc.org/#browse/search/apt=format%3Dapt%20AND%20version%3D2.1.5-isc20220426154040
    RPM: 2.1.5-isc20220426154040.[os]: https://packages.aws.isc.org/#browse/search/yum=format%3Dyum%20AND%20version%3D2.1.5-isc20220426154040*
    Installation instructions are here: https://wiki.isc.org/bin/view/QA/KeaReleaseProcess#4.%20Sanity%20Checks, chapter 4. Sanity Checks, point 9.