Fix test usage of user.Name when user has full name set

When a Linux user has a full name set, the Go user.Name field returns
the full name, rather than the username. The audit_test uses this
value for the output.file.user config, which causes the test to fail
with an unexpected "Could not find uid for user" error returned by
createFileOutput(). This patch fixes the test to use the Username field
instead of the Name field.

audit_test.go

@@ -135,16 +135,16 @@ func Test_createFileOutput(t *testing.T) {
 	g, _ := user.LookupGroupId(strconv.Itoa(gid))
 
 	// travis-ci is silly
-	if u.Name == "" {
-		u.Name = g.Name
+	if u.Username == "" {
+		u.Username = g.Name
 	}
 
 	// gid error
 	c = viper.New()
 	c.Set("output.file.attempts", 1)
 	c.Set("output.file.path", path.Join(os.TempDir(), "go-audit.test.log"))
 	c.Set("output.file.mode", 0644)
-	c.Set("output.file.user", u.Name)
+	c.Set("output.file.user", u.Username)
 	w, err = createFileOutput(c)
 	assert.EqualError(t, err, "Could not find gid for group . Error: group: unknown group ")
 	assert.Nil(t, w)
@@ -165,7 +165,7 @@ func Test_createFileOutput(t *testing.T) {
 	c.Set("output.file.attempts", 1)
 	c.Set("output.file.path", path.Join(os.TempDir(), "go-audit.test.log"))
 	c.Set("output.file.mode", 0644)
-	c.Set("output.file.user", u.Name)
+	c.Set("output.file.user", u.Username)
 	c.Set("output.file.group", g.Name)
 	w, err = createFileOutput(c)
 	assert.Nil(t, err)
@@ -238,8 +238,8 @@ func Test_createOutput(t *testing.T) {
 	g, _ := user.LookupGroupId(strconv.Itoa(gid))
 
 	// travis-ci is silly
-	if u.Name == "" {
-		u.Name = g.Name
+	if u.Username == "" {
+		u.Username = g.Name
 	}
 
 	l, err := net.Listen("tcp", ":0")
@@ -259,7 +259,7 @@ func Test_createOutput(t *testing.T) {
 	c.Set("output.file.attempts", 1)
 	c.Set("output.file.path", path.Join(os.TempDir(), "go-audit.test.log"))
 	c.Set("output.file.mode", 0644)
-	c.Set("output.file.user", u.Name)
+	c.Set("output.file.user", u.Username)
 	c.Set("output.file.group", g.Name)
 
 	w, err = createOutput(c)
@@ -306,7 +306,7 @@ func Test_createOutput(t *testing.T) {
 	c.Set("output.file.attempts", 1)
 	c.Set("output.file.path", path.Join(os.TempDir(), "go-audit.test.log"))
 	c.Set("output.file.mode", 0644)
-	c.Set("output.file.user", u.Name)
+	c.Set("output.file.user", u.Username)
 	c.Set("output.file.group", g.Name)
 	w, err = createOutput(c)
 	assert.Nil(t, err)