bind: upgrade to v9.18.17

Changes:
Update license checksum: only whitespace change.
Update sha256sum for new version.

Additional change:
Do not use version with the foldername, which will result in less diffstat
with future upgrades.

Signed-off-by: Sudip Mukherjee <sudipm.mukherjee@gmail.com>
Signed-off-by: Alexandre Belloni <alexandre.belloni@bootlin.com>