[Minor] Update invocation

src/client/rspamc.c

 			g_string_erase (symbuf, symbuf->len - 1, 1);
 		}
 
-		folded_symbuf = rspamd_header_value_fold ("X-Spam-Symbols",
-				symbuf->str,
+		folded_symbuf = rspamd_header_value_fold ("X-Spam-Symbols", strlen ("X-Spam-Symbols"),
+				symbuf->str, symbuf->len,
 				0, nl_type, ",");
 		rspamd_printf_gstring (added_headers, "X-Spam-Symbols: %v%s",
 				folded_symbuf, line_end);

src/libserver/protocol.c

 					if (task->protocol_flags & RSPAMD_TASK_PROTOCOL_FLAG_MILTER ||
 						!task->message) {
 
-						folded_header = rspamd_header_value_fold ("DKIM-Signature",
-								dkim_sig->str, 80, RSPAMD_TASK_NEWLINES_LF, NULL);
+						folded_header = rspamd_header_value_fold (
+								"DKIM-Signature", strlen ("DKIM-Signature"),
+								dkim_sig->str, dkim_sig->len,
+								80, RSPAMD_TASK_NEWLINES_LF, NULL);
 					}
 					else {
-						folded_header = rspamd_header_value_fold ("DKIM-Signature",
-								dkim_sig->str, 80,
+						folded_header = rspamd_header_value_fold (
+								"DKIM-Signature", strlen ("DKIM-Signature"),
+								dkim_sig->str, dkim_sig->len,
+								80,
 								MESSAGE_FIELD (task, nlines_type),
 								NULL);
 					}
 				dkim_sig = (GString *) dkim_sigs->data;
 
 				if (task->protocol_flags & RSPAMD_TASK_PROTOCOL_FLAG_MILTER) {
-					folded_header = rspamd_header_value_fold ("DKIM-Signature",
-							dkim_sig->str, 80, RSPAMD_TASK_NEWLINES_LF, NULL);
+					folded_header = rspamd_header_value_fold (
+							"DKIM-Signature", strlen ("DKIM-Signature"),
+							dkim_sig->str, dkim_sig->len,
+							80, RSPAMD_TASK_NEWLINES_LF, NULL);
 				}
 				else {
-					folded_header = rspamd_header_value_fold ("DKIM-Signature",
-							dkim_sig->str, 80, MESSAGE_FIELD (task, nlines_type),
+					folded_header = rspamd_header_value_fold (
+							"DKIM-Signature", strlen ("DKIM-Signature"),
+							dkim_sig->str, dkim_sig->len,
+							80, MESSAGE_FIELD (task, nlines_type),
 							NULL);
 				}