Ignore errors from zap logger Sync (#2086)

Added golang CI lint
Reference issue: https://github.com/uber-go/zap/issues/880

Signed-off-by: Sanket Sudake <sanketsudake@gmail.com>

cmd/builder/main.go

@@ -34,12 +34,7 @@ func main() {
 	if err != nil {
 		log.Fatalf("can't initialize zap logger: %v", err)
 	}
-	defer func() {
-		err := logger.Sync()
-		if err != nil {
-			log.Fatal(err)
-		}
-	}()
+	defer logger.Sync()
 
 	shareVolume := os.Args[1]
 	if _, err := os.Stat(shareVolume); err != nil {

cmd/fetcher/main.go

@@ -33,11 +33,6 @@ func main() {
 	if err != nil {
 		log.Fatalf("can't initialize zap logger: %v", err)
 	}
-	defer func() {
-		err := logger.Sync()
-		if err != nil {
-			log.Fatal(err)
-		}
-	}()
+	defer logger.Sync()
 	app.Run(logger)
 }

cmd/fission-bundle/main.go

@@ -255,12 +255,7 @@ Options:
 	if err != nil {
 		log.Fatalf("I can't initialize zap logger: %v", err)
 	}
-	defer func() {
-		err := logger.Sync()
-		if err != nil {
-			log.Fatal(err)
-		}
-	}()
+	defer logger.Sync()
 	version := fmt.Sprintf("Fission Bundle Version: %v", info.BuildInfo().String())
 	arguments, err := docopt.ParseArgs(usage, nil, version)
 	if err != nil {

cmd/preupgradechecks/main.go

@@ -42,12 +42,7 @@ func main() {
 	if err != nil {
 		log.Fatalf("can't initialize zap logger: %v", err)
 	}
-	defer func() {
-		err := logger.Sync()
-		if err != nil {
-			log.Fatal(err)
-		}
-	}()
+	defer logger.Sync()
 
 	usage := `Package to perform operations needed prior to fission installation
 Usage: