have to adjust the @synthesize too

Author: hsoi

WYPopoverController/WYPopoverController.m

@@ -1370,7 +1370,7 @@ @implementation WYPopoverController
 @synthesize delegate;
 @synthesize passthroughViews;
 @synthesize wantsDefaultContentAppearance;
-@synthesize isPopoverVisible;
+@synthesize popoverVisible;
 @synthesize popoverLayoutMargins;
 @synthesize animationDuration;