[geary: 59/66] Improved declaration

[Michael Gratton <mjog src gnome org>]

commit d34832cb366fb7de44e559a962ef1f9900a10419
Author: Chris Heywood <15127-creywood users noreply gitlab gnome org>
Date:   Wed May 13 15:43:40 2020 +1000

    Improved declaration

 src/engine/imap-engine/imap-engine-account-synchronizer.vala | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)
---
diff --git a/src/engine/imap-engine/imap-engine-account-synchronizer.vala 
b/src/engine/imap-engine/imap-engine-account-synchronizer.vala
index ac08c9377..cded00bd2 100644
--- a/src/engine/imap-engine/imap-engine-account-synchronizer.vala
+++ b/src/engine/imap-engine/imap-engine-account-synchronizer.vala
@@ -16,7 +16,7 @@ private class Geary.ImapEngine.AccountSynchronizer :
     private DateTime max_epoch = new DateTime(
         new TimeZone.local(), 2000, 1, 1, 0, 0, 0.0
     );
-    private SyncDetachMonitor sync_detach_monitor = null;
+    private SyncDetachMonitor? sync_detach_monitor = null;
 
 
     public AccountSynchronizer(GenericAccount account) {