Adobe announced that it will discontinue the Adobe Stock Photos service as of April 1, the official reason is "to focus effort in other areas".
There is a Stock Photo uninstaller software available in the Adobe website to uninstall the stock photo module from Adobe Bridge:
Windows version: http://www.adobe.com/support/downloads/product.jsp?product=109&platform=Windows
Mac version: http://www.adobe.com/support/downloads/product.jsp?product=109&platform=Macintosh