GitLocks NullReferenceException

[ThomasAunvik]

Fixes #787

This fixes the NullReferenceException you get, probably cause i dont have any locks.

NullReferenceException: Object reference not set to an instance of an object
GitHub.Unity.ChangesView.<BuildTree>b__42_0 (GitStatusEntry entry)
System.Linq.Enumerable+<CreateSelectIterator>c__Iterator10`2[GitHub.Unity.GitStatusEntry,GitHub.Unity.GitStatusEntryTreeData].MoveNext ()
GitHub.Unity.TreeBase`2[GitHub.Unity.ChangesTreeNode,GitHub.Unity.GitStatusEntryTreeData].Load (IEnumerable`1 treeDatas)
GitHub.Unity.ChangesView.BuildTree ()
GitHub.Unity.ChangesView.MaybeUpdateData ()
GitHub.Unity.ChangesView.OnDataUpdate ()
GitHub.Unity.Window.SwitchView (GitHub.Unity.Subview fromView, GitHub.Unity.Subview toView)
GitHub.Unity.Window.UpdateActiveTab ()
GitHub.Unity.Window.DoToolbarGUI ()
GitHub.Unity.Window.OnUI ()
GitHub.Unity.BaseWindow.OnGUI ()
System.Reflection.MonoMethod.Invoke (System.Object obj, BindingFlags invokeAttr, System.Reflection.Binder binder, System.Object[] parameters, System.Globalization.CultureInfo culture) (at /Users/builduser/buildslave/mono/build/mcs/class/corlib/System.Reflection/MonoMethod.cs:222)
Rethrow as TargetInvocationException: Exception has been thrown by the target of an invocation.
System.Reflection.MonoMethod.Invoke (System.Object obj, BindingFlags invokeAttr, System.Reflection.Binder binder, System.Object[] parameters, System.Globalization.CultureInfo culture) (at /Users/builduser/buildslave/mono/build/mcs/class/corlib/System.Reflection/MonoMethod.cs:232)
System.Reflection.MethodBase.Invoke (System.Object obj, System.Object[] parameters) (at /Users/builduser/buildslave/mono/build/mcs/class/corlib/System.Reflection/MethodBase.cs:115)
UnityEditor.HostView.Invoke (System.String methodName, System.Object obj) (at C:/buildslave/unity/build/Editor/Mono/HostView.cs:291)
UnityEditor.HostView.Invoke (System.String methodName) (at C:/buildslave/unity/build/Editor/Mono/HostView.cs:284)
UnityEditor.HostView.InvokeOnGUI (Rect onGUIPosition) (at C:/buildslave/unity/build/Editor/Mono/HostView.cs:251)```

[StanleyGoldman]

hey @ThomasAunvik
We usually default the fields for views directly.
I pushed to your branch, test it out if you get a chance.

[StanleyGoldman]

You know, I'm not able to reproduce the crash that you are getting here.

[ThomasAunvik]

Crash? Its just an error, and that makes me unable to see the changes.

I managed to reproduce it by just going to master branch, and open unity after i built it, must close after build.

[shana]

I've repro'd the exception and validated the fix 👍