log_services: Fix system dump entries route

With redfish-dump-log enabled, the bmcweb service would throw a
runtime error and exit because the dump entries routes for
Managers and Systems were the same.

The Systems dump entries route should be
'/redfish/v1/Systems/system/LogServices/Dump/Entries/'

Tested:
With redfish-dump-log enabled,
 - bmcweb service does not throw runtime error
 - Redfish Service Validator passes

Signed-off-by: Charles Boyer <Charles.Boyer@fii-usa.com>
Change-Id: I0ffd19bfc643cb8a3be3c5c2cd88c270ec974267