added hash check for node edit

Signed-off-by: Christian Goll <cgoll@suse.de>

internal/pkg/node/hash.go

@@ -2,6 +2,7 @@ package node
 
 import (
 	"crypto/sha256"
+	"encoding/hex"
 
 	"github.com/hpcng/warewulf/internal/pkg/wwlog"
 	"gopkg.in/yaml.v2"
@@ -24,3 +25,11 @@ func (config *NodeYaml) Hash() [32]byte {
 	}
 	return sha256.Sum256(data)
 }
+
+/*
+Return the hash as string
+*/
+func (config *NodeYaml) StringHash() string {
+	buffer := config.Hash()
+	return hex.EncodeToString(buffer[:])
+}