Manage empty image name

And avoid removing charts if there are problems before generating the
helm chart

fix #6

cmd/utils.go

@@ -103,6 +103,10 @@ func Convert(composeFile, appVersion, appName, chartDir string, force bool) {
 		os.Exit(1)
 	}
 
+	// Parse the compose file now
+	p := compose.NewParser(composeFile)
+	p.Parse(appName)
+
 	dirname := filepath.Join(chartDir, appName)
 	if _, err := os.Stat(dirname); err == nil && !force {
 		response := ""
@@ -133,10 +137,6 @@ func Convert(composeFile, appVersion, appName, chartDir string, force bool) {
 		os.Exit(1)
 	}
 
-	// Parse the compose file now
-	p := compose.NewParser(composeFile)
-	p.Parse(appName)
-
 	// start generator
 	generator.Generate(p, Version, appName, appVersion, ComposeFile, dirname)