Properly get the conf.d folder
Properly get the conf.d folder

Currently, it only loads the conf.d folder based on
the statically defined default config file location.

It should take into account the config-file argument
passed.

The Config object already has a get_confd_path method
which does this, and it should be used instead.

Partially-Implements: blueprint add-windows-support

Change-Id: I406b1773920d0b546956452da5003b3f27de8bc0

sapcc/monasca-agent,sapcc/monasca-agent,sapcc/monasca-agent