Fix Error "Service Access is denied" in service collector useApi

[alvarocabanas]

Fix error preventing to collect certain restricted services when using the service collector in api mode "useApi".
Since the handler used sets by default SC_MANAGER_ALL_ACCESS when creating a service handler, in certain windows distributions and for certain services, it is not possible to open a connection to those services that are restricted.
Opening the service with GENERIC_READ fixes the issue.

I've opened this PR fixing the issue #1036