Bump SONAME of libzfs and libzpool before 2.3.0 release

[Harry-Chen]

Motivation and Context

The ABI of libzfs and libzpool have breaking changes since last SONAME bump in commit fe6babc:

• libzfs: zpool_print_unsup_feat removed (used by zpool cmd).
• libzpool: multiple ddt_* symbols removed (used by zdb cmd), and many more.

Bump them to avoid ABI breakage.

See: #11817

cc @behlendorf

Description

See my commits. And here's the dpkg-gensymbols output comparing symbols from 2.3.0-rc1 to 2.2.6, for reference:

zfs-symbols.patch

How Has This Been Tested?

Compiled on my machine. Wait for CI run.

Types of changes

• Bug fix (non-breaking change which fixes an issue)
• New feature (non-breaking change which adds functionality)
• Performance enhancement (non-breaking change which improves efficiency)
• Code cleanup (non-breaking change which makes code smaller or more readable)
• Breaking change (fix or feature that would cause existing functionality to change)
• Library ABI change (libzfs, libzfs_core, libnvpair, libuutil and libzfsbootenv)
• Documentation (a change to man pages or other documentation)

Checklist:

• My code follows the OpenZFS code style requirements.
• I have updated the documentation accordingly.
• I have read the contributing document.
• I have added tests to cover my changes.
• I have run the ZFS Test Suite with this change applied.
• All commit messages are properly formatted and contain Signed-off-by.

[satmandu]

Do any of the ABI changes affect programs shipped outside of OpenZFS (i.e., are any external consumers affected?)?

I assume that zpool and zdb are always packaged with OpenZFS, so they will always be packaged with a corresponding libzfs and libzpool and thus never break?