patch 8.0.0352: not easy to see when a typval needs to be cleared

Problem:    The condition for when a typval needs to be cleared is too
            complicated.
Solution:   Init the type to VAR_UNKNOWN and clear it always.
diff --git a/src/version.c b/src/version.c
index b51f04d..021704a 100644
--- a/src/version.c
+++ b/src/version.c
@@ -765,6 +765,8 @@
 static int included_patches[] =
 {   /* Add new patch number below this line */
 /**/
+    352,
+/**/
     351,
 /**/
     350,