add background fetch to log + background fetch respects git defaults (since you have no explicit option to use)

Author: Thomas Michiels

src/Commands/Fetch.cs

@@ -5,7 +5,7 @@ namespace SourceGit.Commands
 {
     public class Fetch : Command
     {
-        public Fetch(string repo, string remote, bool noTags, bool force)
+        public Fetch(string repo, string remote, bool? noTags, bool force)
         {
             _remote = remote;
 
@@ -14,7 +14,8 @@ public Fetch(string repo, string remote, bool noTags, bool force)
 
             var builder = new StringBuilder(512);
             builder.Append("fetch --progress --verbose ");
-            builder.Append(noTags ? "--no-tags " : "--tags ");
+            if (noTags.HasValue)
+                builder.Append(noTags.Value ? "--no-tags " : "--tags ");
             if (force)
                 builder.Append("--force ");
             builder.Append(remote);

src/ViewModels/Repository.cs

@@ -1850,21 +1850,28 @@ private async Task AutoFetchOnUIThread()
                     remotes.Add(r.Name);
 
                 IsAutoFetching = true;
+                var log = CreateLog("background Fetch");
 
                 if (_settings.FetchAllRemotes)
                 {
                     foreach (var remote in remotes)
-                        await new Commands.Fetch(FullPath, remote, false, false) { RaiseError = false }.RunAsync();
+                        await new Commands.Fetch(FullPath, remote, null, false) { RaiseError = false }
+                            .Use (log)
+                            .RunAsync();
                 }
                 else if (remotes.Count > 0)
                 {
                     var remote = string.IsNullOrEmpty(_settings.DefaultRemote) ?
                         remotes.Find(x => x.Equals(_settings.DefaultRemote, StringComparison.Ordinal)) :
                         remotes[0];
 
-                    await new Commands.Fetch(FullPath, remote, false, false) { RaiseError = false }.RunAsync();
+                    await new Commands.Fetch(FullPath, remote, null, false) { RaiseError = false }
+                        .Use (log)
+                        .RunAsync();
                 }
 
+                log.Complete();
+
                 _lastFetchTime = DateTime.Now;
                 IsAutoFetching = false;
             }