Allows errors from plugin initialization to bubble up (#8926)
Allows errors from plugin initialization to bubble up (#8926)

Prior to this change, if plugin initialization fails, the error message from plugin init
would get cleared when trying to unload the DSO.
duke8253/trafficserver,vmamidi/trafficserver,vmamidi/trafficserver,vmamidi/trafficserver,vmamidi/trafficserver,SolidWallOfCode/trafficserver,SolidWallOfCode/trafficserver,SolidWallOfCode/trafficserver,vmamidi/trafficserver,duke8253/trafficserver,duke8253/trafficserver,SolidWallOfCode/trafficserver,SolidWallOfCode/trafficserver,SolidWallOfCode/trafficserver,SolidWallOfCode/trafficserver,duke8253/trafficserver,duke8253/trafficserver,duke8253/trafficserver,duke8253/trafficserver,vmamidi/trafficserver