Do some build / test-integration fixes

- target generate-webui depends on build-webui
- generate-webui will run only if the folder static does not exists
- create compose project before starting it >_<'', otherwise it does
  nothing :'D

Signed-off-by: Vincent Demeester <vincent@sbr.pm>

integration/integration_test.go

@@ -87,6 +87,9 @@ func (s *BaseSuite) createComposeProject(c *check.C, name string) {
 	c.Assert(err, checker.IsNil)
 	s.composeProject = composeProject
 
+	err = composeProject.Create()
+	c.Assert(err, checker.IsNil)
+
 	s.started = make(chan bool)
 	s.stopped = make(chan bool)
 	s.deleted = make(chan bool)
@@ -96,7 +99,8 @@ func (s *BaseSuite) createComposeProject(c *check.C, name string) {
 
 	composeProject.AddListener(s.listenChan)
 
-	composeProject.Start()
+	err = composeProject.Start()
+	c.Assert(err, checker.IsNil)
 
 	// Wait for compose to start
 	<-s.started