vircrypto: provide constants for hash sizes
vircrypto: provide constants for hash sizes

The callers needing to know the size of the resulting digest
rely on _DIGEST_SIZE constants from gnulib.

Introduce VIR_CRYPTO_HASH_SIZE_ constants to remove the dependency.

Signed-off-by: Ján Tomko <4cab11cfb98d3c937327354a78eb07dbb6ee2bc6@redhat.com>

libvirt/libvirt,crobinso/libvirt,jfehlig/libvirt,jardasgit/libvirt,eskultety/libvirt,eskultety/libvirt,jfehlig/libvirt,andreabolognani/libvirt,andreabolognani/libvirt,andreabolognani/libvirt,jardasgit/libvirt,libvirt/libvirt,zippy2/libvirt,nertpinx/libvirt,nertpinx/libvirt,libvirt/libvirt,andreabolognani/libvirt,fabianfreyer/libvirt,libvirt/libvirt,crobinso/libvirt,nertpinx/libvirt,jardasgit/libvirt,zippy2/libvirt,fabianfreyer/libvirt,jardasgit/libvirt,jardasgit/libvirt,zippy2/libvirt,olafhering/libvirt,jfehlig/libvirt,crobinso/libvirt,nertpinx/libvirt,olafhering/libvirt,jfehlig/libvirt,eskultety/libvirt,andreabolognani/libvirt,olafhering/libvirt,eskultety/libvirt,fabianfreyer/libvirt,eskultety/libvirt,fabianfreyer/libvirt,zippy2/libvirt,olafhering/libvirt,fabianfreyer/libvirt,nertpinx/libvirt,crobinso/libvirt