DPM: fix dmlite config for DPM 1.8.8
(default config is 1.8.8 compliant, define DPM_VERSION=1.8.7 for previous version)
DPM: define default values for number of DPM fast and slow threads
(adjust defaults to values recommended by DPM developers)
DPM: reorganize dmlite config to ensure that the right plugins are loaded
and that dmlite is always configured except if only RFIO is used.
(also restart DPM daemons after a dmlite config change)
Merge pull request #68 from jouvin/umd3-dpm-1.8.8

Fix DPM for 1.8.8 support