It's possibly that when trying to upload a backup the free space check
will output scientific notation resulting in an incorrect "There is not
enough space on disk" error.
The free space check uses the Linux `print` command which could return a
number using scientific notation like `1.60459e+10` and when ruby
converts it to an integer it will have the value of `1` instead of
`16045879296`. Which means even though you have 16GB of free space you
could not upload a 1GB backup file.
This commit uses the `printf` command instead which allows you to
specify that you do not want scientific notation.
I'm not sure why this hasn't been an issue before, but I was
experiencing it locally in development.
Blake Erickson
b73a133bb5