webmmfsource: removed old IMFMediaSource::Start code
webmmfsource: removed old IMFMediaSource::Start code

This was old code that had long been commented out, but it was
the original implementation of the Start method.  It is useful
for informational reasons, as it supplements the API docs.

Change-Id: I9183e09027e863eebd6156e38506579aef7fd417

kleopatra999/webm.webmdshow,ericmckean/webm.webmdshow,Acidburn0zzz/webm.webmdshow,kalli123/webm.webmdshow,abwiz0086/webm.webmdshow,kim42083/webm.webmdshow,webmproject/webmdshow,brion/webmdshow,ericmckean/webm.webmdshow,gshORTON/webm.webmdshow,webmproject/webmdshow,matanbs/webm.webmdshow,webmproject/webmdshow,abwiz0086/webm.webmdshow,Acidburn0zzz/webm.webmdshow,kalli123/webm.webmdshow,abwiz0086/webm.webmdshow,gshORTON/webm.webmdshow,brion/webmdshow,Maria1099/webm.webmdshow,Maria1099/webm.webmdshow,matanbs/webm.webmdshow,kalli123/webm.webmdshow,zofuthan/webmdshow,Maria1099/webm.webmdshow,zofuthan/webmdshow,ericmckean/webm.webmdshow,kim42083/webm.webmdshow,altogother/webm.webmdshow,kleopatra999/webm.webmdshow,iniwf/webm.webmdshow,Acidburn0zzz/webm.webmdshow,iniwf/webm.webmdshow,kim42083/webm.webmdshow,ericmckean/webm.webmdshow,iniwf/webm.webmdshow,Acidburn0zzz/webm.webmdshow,kalli123/webm.webmdshow,altogother/webm.webmdshow,kim42083/webm.webmdshow,gshORTON/webm.webmdshow,abwiz0086/webm.webmdshow,Maria1099/webm.webmdshow,altogother/webm.webmdshow,matanbs/webm.webmdshow,brion/webmdshow,iniwf/webm.webmdshow,matanbs/webm.webmdshow,altogother/webm.webmdshow,webmproject/webmdshow,brion/webmdshow,gshORTON/webm.webmdshow,kleopatra999/webm.webmdshow,zofuthan/webmdshow,zofuthan/webmdshow,brion/webmdshow,kleopatra999/webm.webmdshow