Fix issue #i119524#: [From Symphony]Can not open the sample ppt file which contain vb controls in the slide master.

* subversion/main/sd/source/ui/unoidl/unomodel.cxx
[]Before initializeDocument,should check whether it is in loading process

Patch by: Yin Bing <steve.yin.aoo@gmail.com>
Suggested by:Wang Zhe <kingwisemmx@gmail.com>
Found by: Du Jing <jbjdujing@gmail.com>
Review by: Wang Zhe <kingwisemmx@gmail.com>