multiboot_select plugin check volume root for valid firmware -- Try 2
I'm not sure why but on my fuze v2 I don't get the '.' nd '..'
directories back from readdir
that make removing '.' to find /.rockbox inconsistent
Instead filter out files and strcmp the incoming dirs
to BOOTDIR (.rockbox) and clear it when they match
Change-Id: Id8f3312cb3ae624dff1be21f745034c08c4ae1a7