zdtm: typo fix

expr ns/user/static/env00 ns/user
expr: syntax error
Signed-off-by: Andrew Vagin <avagin@openvz.org>
Signed-off-by: Pavel Emelyanov <xemul@parallels.com>

test/zdtm.sh

@@ -579,7 +579,7 @@ run_test()
 			echo "Skip $test"
 			return 0
 		fi
-		expr $test 'ns/user' > /dev/null && {
+		expr $test : 'ns/user' > /dev/null && {
 			echo "Skip $test"
 			return 0
 		}