patch 8.1.0410: the ex_copen() function is too long

Problem:    The ex_copen() function is too long.
Solution:   Refactor to split off two functions. (Yegappan Lakshmanan)
diff --git a/src/version.c b/src/version.c
index 2726e63..10d8e49 100644
--- a/src/version.c
+++ b/src/version.c
@@ -795,6 +795,8 @@
 static int included_patches[] =
 {   /* Add new patch number below this line */
 /**/
+    410,
+/**/
     409,
 /**/
     408,