do not register erp5_web_blog skin folder in all skin selections.

because it overrides WebPage_viewAsWeb.

bt5/erp5_web_blog/RegisteredSkinSelectionTemplateItem/registered_skin_selection.xml

+<registered_skin_selection>
+ <skin_folder_selection>
+  <skin_folder>erp5_web_blog</skin_folder>
+  <skin_selection>Blog</skin_selection>
+ </skin_folder_selection>
+</registered_skin_selection>
\ No newline at end of file

bt5/erp5_web_blog/bt/revision

-91
\ No newline at end of file
+92
\ No newline at end of file

bt5/erp5_web_blog/bt/template_registered_skin_selection_list

+erp5_web_blog | Blog
\ No newline at end of file