Fix with nettle >=4

Index: src/crypto/nettle/hash.c
--- src/crypto/nettle/hash.c.orig
+++ src/crypto/nettle/hash.c
@@ -21,7 +21,7 @@
 #include <stdlib.h>
 #include <nettle/md5.h>
 #include <nettle/sha1.h>
-#include <nettle/sha.h>
+#include <nettle/sha2.h>
 
 struct crypto_hash {
 	union {
