tdf#139480 sc: Un/Track changes now marks spreadsheet as unsaved

It makes it consistent with SW, which is why I went ahead
with this without asking any questions.

Change-Id: Ibb8f4149bfb3bd785c35772d0ff399f60c0d1c72
Reviewed-on: https://gerrit.libreoffice.org/c/core/+/140933
Tested-by: Justin Luth <jluth@mail.com>
Reviewed-by: Justin Luth <jluth@mail.com>
diff --git a/sc/source/core/data/documen2.cxx b/sc/source/core/data/documen2.cxx
index 124089b..f784d51 100644
--- a/sc/source/core/data/documen2.cxx
+++ b/sc/source/core/data/documen2.cxx
@@ -277,11 +277,17 @@ sal_uInt32 ScDocument::GetDocumentID() const
void ScDocument::StartChangeTracking()
{
    if (!pChangeTrack)
    {
        pChangeTrack.reset( new ScChangeTrack( *this ) );
        if (mpShell)
            mpShell->SetModified();
    }
}

void ScDocument::EndChangeTracking()
{
    if (pChangeTrack && mpShell)
        mpShell->SetModified();
    pChangeTrack.reset();
}