BUG: Replace relative imports in cversions.py.

Scripts should not use relative imports as they won't work in a
non-package environment.
MAINT: Update API version and API hash.

In preparation for the 1.8 release, update the API version to
0x00000009 and the API hash to f99a02b75bd60205d1afe1eed080fd53.
Merge pull request #3619 from charris/update-ABI-version-and-hash

Update abi version and hash