Code review comment for ~pieq/plainbox-provider-checkbox:1660386-mount-drive-before-storage-tests

This is running against a disk with a label and a partition, but the partition is not formatted:
ubuntu@wildorange:~$ sudo ./storage_test sdc
/dev/sdc is a block device
/dev/sdc reports a size of 147GB.
/dev/sdc is not mounted. It must be mounted before testing.
Mounting /dev/sdc into /tmp/drive/sdc...
mount: wrong fs type, bad option, bad superblock on /dev/sdc,
       missing codepage or helper program, or other error

       In some cases useful info is found in syslog - try
       dmesg | tail or so.
Running bonnie++ on /dev/sdc...
Putting scratch disk at
    Disk /dev/sdc has MB available
    System has 56354MB RAM
    We need 112708MB of disk space for testing
    Insufficient disk space available for defaults.
    reducing memory footprint to be 1/2 of free disk space.
./storage_test: line 25: /2: syntax error: operand expected (error token is "/2")

Same error at line 25, so that should probably be fixed.