CLI: Fix config flag being ignored

Passing --config had no effect when passed.  It will now be applied as
the last config file and before any env var overrrides.

pkg/setting/setting.go

@@ -164,9 +164,13 @@ func loadEnvVariableOverrides() {
 	}
 }
 
-func NewConfigContext() {
+func NewConfigContext(config string) {
 	configFiles := findConfigFiles()
 
+	if config != "" {
+		configFiles = append(configFiles, config)
+	}
+
 	//log.Info("Loading config files: %v", configFiles)
 	var err error
 

pkg/setting/setting_test.go

@@ -15,7 +15,7 @@ func TestLoadingSettings(t *testing.T) {
 	Convey("Testing loading settings from ini file", t, func() {
 
 		Convey("Given the default ini files", func() {
-			NewConfigContext()
+			NewConfigContext("")
 
 			So(AppName, ShouldEqual, "Grafana")
 			So(AdminUser, ShouldEqual, "admin")
@@ -23,7 +23,7 @@ func TestLoadingSettings(t *testing.T) {
 
 		Convey("Should be able to override via environment variables", func() {
 			os.Setenv("GF_SECURITY_ADMIN_USER", "superduper")
-			NewConfigContext()
+			NewConfigContext("")
 
 			So(AdminUser, ShouldEqual, "superduper")
 		})