With certain CMIS host URLs, it is possible that exception handler
in Content::getObject() will recursively call itself with the same
data (xParent from the same URL).

This patch checks if the new URL is not the same as own, to avoid
this.

Change-Id: Ifaeb4ff27a9c809c5c96fa35ec190c3263a8fe62
Reviewed-on: https://gerrit.libreoffice.org/26977Reviewed-by: Andras Timar <andras.timar@collabora.com>
Tested-by: Andras Timar <andras.timar@collabora.com>