invalid literal for float()

[jlay79]

For node pools that started with a hypen (perhaps on clusters with tiers configured), the first letter in the output is a hypen ('-'). This throws off the indexing to identify the hdd percent.

Traceback (most recent call last):
  File "nodepool_util_email.py", line 105, in <module>
    main()
  File "nodepool_util_email.py", line 88, in main
    hdd_pct = float(pool[5].strip('%'))
ValueError: invalid literal for float(): 5.17000P