patch 8.2.4951: smart indenting done when not enabled

Problem:    Smart indenting done when not enabled.
Solution:   Check option values before setting can_si. (closes #10420)
diff --git a/src/version.c b/src/version.c
index 8d3f2e7..c9ec301 100644
--- a/src/version.c
+++ b/src/version.c
@@ -747,6 +747,8 @@
 static int included_patches[] =
 {   /* Add new patch number below this line */
 /**/
+    4951,
+/**/
     4950,
 /**/
     4949,