package/bind: drop unneeded static openssl workarounds

package/bind: drop unneeded static openssl workarounds

bind can't be built statically since commit
6045904752b06a8b8e52ba8fc2e49a8548964e8d

So drop uneeded LIBS="-lz" which was added by commit
80ebf12906afc3a1e5f4e5682d4c5dc0779a556a to fix static build with
openssl

Also, drop ac_cv_func_EVP_{sha256,sha384,sha512} that was also added to
fix tests in static build by commit
26aefa672c96caefc17adf59a9ab3d327114ad36

Signed-off-by: Fabrice Fontaine <fontaine.fabrice@gmail.com>
Signed-off-by: Thomas Petazzoni <thomas.petazzoni@bootlin.com>