Add disk.inodeusage and fix disk.usage logic
Add disk.inodeusage and fix disk.usage logic

Previously, disk.usage was returning a dictionary where the key was in
the "Filesystem" column. It seemed proper to return every  filesystem,
even the virtual ones so the dict key was changed to  the  mountpoint.

$ df -P
Filesystem         1024-blocks      Used Available Capacity Mounted on
/dev/sda8            177822980  12504764 156285272       8% /
none                   6154104       312   6153792       1% /dev
none                   6161372      3736   6157636       1% /dev/shm
none                   6161372       336   6161036       1% /var/run
none                   6161372         0   6161372       0% /var/lock
/dev/sda1               101086     85423     15663      85% /boot
/dev/sda5            240308484 219822840  20485644      92% /home
/dev/sda7             54791132   1104204  50903672       3% /var

This can be changed to skip anything that has a Filesystem of none
down the road, but I don't have any non-Linux hosts  to  test  on.

saltstack/salt,saltstack/salt,saltstack/salt,saltstack/salt,saltstack/salt