qga: save state directory in ga_install_service()

qga: save state directory in ga_install_service()

If the user selects a non-default state directory at service installation
time, we should remember it in the registered service.

Signed-off-by: Laszlo Ersek <lersek@redhat.com>
Signed-off-by: Michael Roth <mdroth@linux.vnet.ibm.com>
(cherry picked from commit a839ee77c786a8200c76ca92f697eebf6bcc9aa3)

* modified to save state_dir unconditionally an avoid reliance on
  uncommitted CSIDL_COMMON_APPDATA dependencies

Signed-off-by: Michael Roth <mdroth@linux.vnet.ibm.com>