stop attempting to handle errors when turning on preview

Author: Danny McClanahan

markdown-mode.el

@@ -6718,8 +6718,7 @@ before regenerating font-lock rules for extensions."
   :group 'markdown-mode
   :lighter " MD-Preview"
   (if markdown-live-preview-mode
-      (condition-case nil (markdown-live-preview-setup)
-        (error (markdown-live-preview-mode -1)))
+      (markdown-live-preview-setup)
     (markdown-live-preview-teardown-source)))