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".

src/version.c

@@ -695,6 +695,8 @@ static char *(features[]) =
 
 static int included_patches[] =
 {   /* Add new patch number below this line */
+/**/
+    1657,
 /**/
     1656,
 /**/