[EFL] Use EINA_SAFETY_ON_NULL_RETURN_VAL for NULL checks instead of EINA_SAFETY_ON_FA...

[EFL] Use EINA_SAFETY_ON_NULL_RETURN_VAL for NULL checks instead of EINA_SAFETY_ON_FALSE_RETURN_VAL.
https://bugs.webkit.org/show_bug.cgi?id=70091

Patch by Grzegorz Czajkowski <g.czajkowski@samsung.com> on 2011-11-15
Reviewed by Filip Pizlo.

Replaces EINA_SAFETY_ON_FALSE_RETURN_VAL by EINA_SAFETY_ON_NULL_RETURN_VAL for NULL checks in compliance
with WebKit-EFL functions.

* ewk/ewk_frame.cpp:
(ewk_frame_contents_set):
(ewk_frame_contents_alternate_set):

git-svn-id: https://svn.webkit.org/repository/webkit/trunk@100261 268f45cc-cd09-0410-ab3c-d52691b4dbfc