only execute last test when we are a pty

src/tests/lxc-test-lxc-attach

@@ -190,14 +190,16 @@ fi
 
 rm -f $out $err
 
-# Test whether logging pty output to a file works.
-trap "rm -f /tmp/ptylog" EXIT INT QUIT PIPE
-lxc-attach -n busy -L /tmp/ptylog -- hostname || FAIL "to allocate or setup pty"
-if [ $allocate_pty == "pty" ] && [ ! -s /tmp/ptylog ]; then
-        FAIL "lxc-attach -n busy -L /tmp/ptylog -- hostname"
-fi
+if [ $allocate_pty = "pty" ]; then
+	# Test whether logging pty output to a file works.
+	trap "rm -f /tmp/ptylog" EXIT INT QUIT PIPE
+	lxc-attach -n busy -L /tmp/ptylog -- hostname || FAIL "to allocate or setup pty"
+	if [ ! -s /tmp/ptylog ]; then
+		FAIL "lxc-attach -n busy -L /tmp/ptylog -- hostname"
+	fi
 
-rm -f /tmp/ptylog
+	rm -f /tmp/ptylog
+fi
 
 lxc-destroy -n busy -f