[REVIEW 3-5][REVIEW 3-5-1 ?] fix crash using edit instance from xforms "Data navigator" dialog

[Noel Power]

http://cgit.freedesktop.org/libreoffice/core/commit/?id=7b860d4970604f08ebd2e818bfd63891dd940804

should fix the problem, it seems that commit 
f7f47366ea78a71853fcaca2fa402bef667d9cce introduced a 'delete(pPage);' ( 
it seems from the comment to silence some cppcheck error ) but that 
delete doesn't imo make any sense.

Noel