Chore: remove use of == false (#17036)

Interestingly enough, golint or revive doesn't not prohibit
the use that construction :)

Ref #17035

pkg/middleware/auth_proxy.go

@@ -20,17 +20,17 @@ func initContextWithAuthProxy(store *remotecache.RemoteCache, ctx *m.ReqContext,
 	})
 
 	// Bail if auth proxy is not enabled
-	if auth.IsEnabled() == false {
+	if !auth.IsEnabled() {
 		return false
 	}
 
 	// If the there is no header - we can't move forward
-	if auth.HasHeader() == false {
+	if !auth.HasHeader() {
 		return false
 	}
 
 	// Check if allowed to continue with this IP
-	if result, err := auth.IsAllowedIP(); result == false {
+	if result, err := auth.IsAllowedIP(); !result {
 		ctx.Handle(407, err.Error(), err.DetailsError)
 		return true
 	}