Bug 1012386 - Release the CGImage we addref'd in DrawTargetCG::CopySurface. r=jrmuizel

gfx/2d/DrawTargetCG.cpp

@@ -1253,6 +1253,7 @@ DrawTargetCG::CopySurface(SourceSurface *aSurface,
     CGContextDrawImage(mCg, flippedRect, image);
 
     CGContextRestoreGState(mCg);
+    CGImageRelease(image);
   }
 }