Fix potential nil pointer problem when using multierror pkg (#1311)

pkg/fission-cli/cmd/spec/spec.go

@@ -297,7 +297,7 @@ func (fr *FissionResources) validateFunctionReference(functions map[string]bool,
 }
 
 func (fr *FissionResources) Validate(c *cli.Context) error {
-	var result *multierror.Error
+	result := &multierror.Error{}
 
 	// check references: both dangling refs + garbage
 	//   packages -> archives

pkg/fission-cli/package.go

@@ -488,7 +488,7 @@ func fileChecksum(fileName string) (*fv1.Checksum, error) {
 // includeFiles, but is ignored if there's more than one includeFile.
 func createArchive(client *client.Client, includeFiles []string, noZip bool, specDir string, specFile string) *fv1.Archive {
 
-	var errs *multierror.Error
+	errs := &multierror.Error{}
 
 	// check files existence
 	for _, path := range includeFiles {

pkg/fission-cli/spec.go

@@ -160,7 +160,7 @@ func readSpecs(specDir string) (*spec.FissionResources, error) {
 		},
 	}
 
-	var result *multierror.Error
+	result := &multierror.Error{}
 
 	// Users can organize the specdir into subdirs if they want to.
 	err := filepath.Walk(specDir, func(path string, info os.FileInfo, err error) error {