volumes: only wait for 5 seconds for mount status

mountpoint -q can never exit if the nfs mount disappears, for example

src/test/shell-test.js

@@ -52,27 +52,32 @@ describe('shell', function () {
         await safe(shell.promises.sudo('test', [ RELOAD_NGINX_CMD, 'nginx' ], {}));
     });
 
-    it('execSync a valid shell program', function (done) {
+    it('exec a valid shell program', function (done) {
         shell.exec('test', 'ls -l | wc -c', {}, function (error) {
             done(error);
         });
     });
 
-    it('execSync a valid shell program (promises)', async function () {
+    it('exec a valid shell program (promises)', async function () {
         await shell.promises.exec('test', 'ls -l | wc -c', {});
     });
 
-    it('execSync throws for invalid program', function (done) {
+    it('exec throws for invalid program', function (done) {
         shell.exec('test', 'cannotexist', {}, function (error) {
             expect(error).to.be.ok();
             done();
         });
     });
 
-    it('execSync throws for failed program', function (done) {
+    it('exec throws for failed program', function (done) {
         shell.exec('test', 'false', {}, function (error) {
             expect(error).to.be.ok();
             done();
         });
     });
+
+    it('exec times out properly', async function () {
+        const [error] = await safe(shell.promises.exec('sleeping', 'sleep 20', { timeout: 1000 }));
+        expect(error.signal).to.be('SIGTERM'); // somtimes code is ETIMEOUT
+    });
 });