patch 8.1.0850: test for 'backupskip' is not correct

Problem:    Test for 'backupskip' is not correct.
Solution:   Split the option in parts and use expand(). (Michael Soyka)
diff --git a/src/version.c b/src/version.c
index 864ca44..31bfb9a 100644
--- a/src/version.c
+++ b/src/version.c
@@ -784,6 +784,8 @@
 static int included_patches[] =
 {   /* Add new patch number below this line */
 /**/
+    850,
+/**/
     849,
 /**/
     848,