test/unit: Use plain `tclsh' to run the code.

diff --git a/test/unit b/test/unit
index 73c01ae..9f5aee3 100755 (executable)
--- a/test/unit
+++ b/test/unit
@@ -1,4 +1,4 @@
-#! /usr/bin/tclsh8.5
+#! /usr/bin/tclsh
 ### -*-tcl-*-
 
 source [file join [file dirname $argv0] "../lib/func.tcl"]