[orca] Remove non-existent setting

[Joanmarie Diggs <joanied src gnome org>]

commit ab3faee8e7c5b88ebf06f13632bd7fe0a4119f69
Author: Joanmarie Diggs <jdiggs igalia com>
Date:   Sat Jun 30 15:14:06 2018 -0400

    Remove non-existent setting

 src/orca/settings.py | 1 -
 1 file changed, 1 deletion(-)
---
diff --git a/src/orca/settings.py b/src/orca/settings.py
index ef56f0562..ad96e58ec 100644
--- a/src/orca/settings.py
+++ b/src/orca/settings.py
@@ -96,7 +96,6 @@ userCustomizableSettings = [
     "enableContractedBraille",
     "brailleContractionTable",
     "enableMouseReview",
-    "mouseDwellDelay",
     "speakCellCoordinates",
     "speakSpreadsheetCoordinates",
     "speakCellSpan",