rmformat detects CD-ROM as a removable media, use disklist -r instead

rmformat is not the best choice for getting list of removable medias. One of my SmartOS node has DVD-RAM and it is reported by rmformat. 

Example output:
Looking for devices...
     1. Logical Node: /dev/rdsk/c1t0d0p0
        Physical Node: /pci@0,0/pci1014,3a3a@1d,7/storage@5/disk@0,0
        Connected Device: Kingston DT Micro         PMAP
        Device Type: Removable
        Bus: USB
        Size: 7.5 GB
        Label: <Unknown>
        Access permissions: <Unknown>
     2. Logical Node: /dev/rdsk/c3t0d0p0
        Physical Node: /pci@0,0/pci-ide@1f,2/ide@0/sd@0,0
        Connected Device: MATSHITA DVD-RAM UJ890    SAA5
        Device Type: DVD Reader/Writer
        Bus: IDE
        Size: <Unknown>
        Label: <Unknown>
        Access permissions: <Unknown>

This patch fixes this and uses disklist -r, which reports removable disks only.