Replace DsKeyToCidV1Raw() with DsKeyToCidV1()

Allow passing in whatever codec type the user wants

key.go

@@ -40,11 +40,12 @@ func DsKeyToMultihash(dsKey datastore.Key) (mh.Multihash, error) {
 }
 
 // DsKeyToCidV1Raw converts the given Key (which should be a raw multihash
-// key) to a Cid V1 of raw type.
-func DsKeyToCidV1Raw(dsKey datastore.Key) (cid.Cid, error) {
+// key) to a Cid V1 of the given type (see
+// https://godoc.org/github.com/ipfs/go-cid#pkg-constants).
+func DsKeyToCidV1(dsKey datastore.Key, codecType uint64) (cid.Cid, error) {
 	hash, err := DsKeyToMultihash(dsKey)
 	if err != nil {
 		return cid.Cid{}, err
 	}
-	return cid.NewCidV1(cid.Raw, hash), nil
+	return cid.NewCidV1(codecType, hash), nil
 }

key_test.go

@@ -17,7 +17,7 @@ func TestKey(t *testing.T) {
 		t.Fatal("should have parsed the same multihash")
 	}
 
-	c2, err := DsKeyToCidV1Raw(dsKey)
+	c2, err := DsKeyToCidV1(dsKey, cid.Raw)
 	if err != nil || c.Equals(c2) || c2.Type() != cid.Raw || c2.Version() != 1 {
 		t.Fatal("should have been converted to CIDv1-raw")
 	}