fix bashism (merge from devbr6 https://trac.osgeo.org/grass/changeset/45002)

git-svn-id: https://svn.osgeo.org/grass/grass/trunk@45259 15284696-431f-4ddb-bdfa-cd5b030d7da7

lib/vector/dglib/examples/rtest03.sh

@@ -1,4 +1,4 @@
-#!/bin/sh
+#!/bin/bash
 
 
 rm -f X1 X2 X3 X1.txt X2.txt X3.txt