tdf#107039: Avoid deadlock by locking the SolarMutex early on in one place

See bug report for backtraces of the deadlocking threads.

Change-Id: I0334118e173c37b6f9596249e1e2f0d196bbab3f
Reviewed-on: https://gerrit.libreoffice.org/47249Tested-by: Jenkins <ci@libreoffice.org>
Reviewed-by: Tor Lillqvist <tml@collabora.com>

framework/source/services/autorecovery.cxx

@@ -1565,6 +1565,7 @@ void SAL_CALL AutoRecovery::documentEventOccured(const css::document::DocumentEv
         (aEvent.EventName == EVENT_ON_SAVEASDONE)
        )
     {
+        SolarMutexGuard g;
         implts_markDocumentAsSaved(xDocument);
         implts_updateDocumentUsedForSavingState(xDocument, SAVE_FINISHED);
     }