require nrpe package before collecting

There was a race condition where collection of virtual resources defined
by nrpe::check and collected by nrpe class could happen before the
directory /etc/nagios/nrpe.d/ would be created. This directory is
created by package nagios-nrpe-server so we depend the collection on
this package.

Change-Id: I1c1d276b4bffb8cea787c5c6c403c0b6152e0216
Merge "require nrpe package before collecting" into production