(5) fix foo_mem_clean() functions to avoid race cond.

mem_clean functions previously free()'d our pointer array without
first checking that the name/interface had properly been unexported from
dbus. checking first better guarantees all operations implicating that date
have ceased, and that it is safe to go ahead and stop the GMainLoop before
immediately returning. this causes the code just after the main_loop_begin()
call to start functioning, in our case the actual free() calls (which are now
*absolutley* safe to call)