[folks] Prevent extra "concurrent" Aggregator prepare() calls from one thread.

[Jeremy Whiting <jpwhiting src gnome org>]

commit 8303d317a57af3caf2521aa636327485f2e7e3b8
Author: Travis Reitter <travis reitter collabora co uk>
Date:   Wed Jul 6 17:58:05 2011 -0700

    Prevent extra "concurrent" Aggregator prepare() calls from one thread.
    
    Helps: bgo#652637 - Don't hold locks across async calls

 folks/individual-aggregator.vala |    1 +
 1 files changed, 1 insertions(+), 0 deletions(-)
---
diff --git a/folks/individual-aggregator.vala b/folks/individual-aggregator.vala
index 5e01949..edc411d 100644
--- a/folks/individual-aggregator.vala
+++ b/folks/individual-aggregator.vala
@@ -544,6 +544,7 @@ public class Folks.IndividualAggregator : Object
               this._non_quiescent_backend_count--;
 
               this._is_prepared = true;
+              this._prepare_pending = false;
               this.notify_property ("is-prepared");
 
               /* Mark the aggregator as having reached a quiescent state if