[orca] Fix for bgo#621675 - Custom zoomer size has zero width (GnomeShell magnifier).

[Joanmarie Diggs <joanied src gnome org>]

commit 0ffd3eb606ca7f2cb98901f637d9cb3b39e21720
Author: Joseph Scheuhammer <clown utoronto ca>
Date:   Tue Jun 15 13:25:26 2010 -0400

    Fix for bgo#621675 - Custom zoomer size has zero width (GnomeShell magnifier).

 src/orca/gsmag.py |    2 +-
 1 files changed, 1 insertions(+), 1 deletions(-)
---
diff --git a/src/orca/gsmag.py b/src/orca/gsmag.py
index 345ca55..14d69b4 100644
--- a/src/orca/gsmag.py
+++ b/src/orca/gsmag.py
@@ -502,7 +502,7 @@ def __setupZoomer(restore=None, left=None, top=None, right=None, bottom=None):
         top = 0
         bottom = _screenHeight
 
-    viewWidth = right = left
+    viewWidth = right - left
     viewHeight = bottom - top
     _roiWidth = viewWidth / settings.magZoomFactor
     _roiHeight = viewHeight / settings.magZoomFactor