nrpe: remove hard coded disk checks

Those checks were converted to use nrpe::monitor instead.
For example see this patch:
https://gerrit.wikimedia.org/r/#/c/110844/
Those checks are not used anywhere else

Change-Id: I8cdee5204a25e82ee14e1a06b2dd4e7740bd248f
Merge "nrpe: remove hard coded disk checks" into production