src/pmdas/linux/proc_partitions.c: remove cdrom from disk indom
src/pmdas/linux/proc_partitions.c: remove cdrom from disk indom

Not sure how this sneaked back in ... at the start of time, floppy
and cdrom devices were excluded from the disk.dev.* metrics.

I've just seen qa/008 failing on bozo, and this change fixes it.

Would be worth reviewing with another set of eyes.

adfernandes/pcp,adfernandes/pcp,adfernandes/pcp,adfernandes/pcp,adfernandes/pcp,adfernandes/pcp,adfernandes/pcp,adfernandes/pcp