Make gh-pages target build the plugin developer guide.
Make gh-pages target build the plugin developer guide.

Change-Id: I64831d4c4843bdc6a2e837ea8dc35c2b686dbca0
Signed-off-by: Brad Geltz <e42f3ad4099980ea02f08e076efbee5cf9d4a803@intel.com>

geopm/geopm,geopm/geopm,geopm/geopm,cmcantalupo/geopm,cmcantalupo/geopm,geopm/geopm,geopm/geopm,cmcantalupo/geopm,cmcantalupo/geopm,cmcantalupo/geopm