test: add checkskip hook

Although there is the skip() macro, this doesn't actually do anything to skip
the test. I looked into adding a test_skip() function in the zdtm lib, but
there didn't seem an easy race-free way to propagate an exit code up to
run_test in zdtm.sh, so we add the checkskip hook for use in the apparmor test
(e.g. when apparmor isn't avialable in the kernel, or is disabled).
Signed-off-by: Tycho Andersen <tycho.andersen@canonical.com>
Signed-off-by: Pavel Emelyanov <xemul@parallels.com>

test/zdtm.sh

@@ -651,6 +651,11 @@ run_test()
 	local rst_args=
 	DUMP_PATH=""
 
+	if [ -f "$test".checkskip ] && [ "$test".checkskip ]; then
+		echo "Skip $test"
+		return 0
+	fi
+
 	if [ $COMPILE_ONLY -eq 1 ]; then
 		echo "Compile $test"
 		make -C $tdir $tname && return 0 || return 1