patch 8.1.2187: error for bad regexp even though regexp is not used

Problem:    Error for bad regexp even though regexp is not used when writing
            a file. (Arseny Nasokin)
Solution:   Ignore regexp errors. (closes #5059)
diff --git a/src/ex_docmd.c b/src/ex_docmd.c
index 4dd7ba2..1d04769 100644
--- a/src/ex_docmd.c
+++ b/src/ex_docmd.c
@@ -4211,7 +4211,8 @@
 		else /* n == 2 */
 		{
 		    expand_T	xpc;
-		    int		options = WILD_LIST_NOTFOUND|WILD_ADD_SLASH;
+		    int		options = WILD_LIST_NOTFOUND
+					       | WILD_NOERROR | WILD_ADD_SLASH;
 
 		    ExpandInit(&xpc);
 		    xpc.xp_context = EXPAND_FILES;