patch 9.0.1657: one more syntax test depends on the system

Problem:    One more syntax test depends on the system.
Solution:   Use "dash" instead of "sh".
diff --git a/src/version.c b/src/version.c
index 535afe7..f847175 100644
--- a/src/version.c
+++ b/src/version.c
@@ -696,6 +696,8 @@
 static int included_patches[] =
 {   /* Add new patch number below this line */
 /**/
+    1657,
+/**/
     1656,
 /**/
     1655,