[gtkpod] autodetection: Prevent double checking of mount points
Every time I start up gtkpod, I get a warning "Newly mounted iPod at '/foo' appears to be already loaded!". The iphone mount point is added twice to the new_ipod_uris list. The attached patch checks if the list of new_ipod_uris already contains the uri and only adds it if it is not already present. This way no message appears anymore.