vds-tool: keep env on sysV service

Update env when SYSTEMCTL_SKIP_REDIRECT is set instead of dropping
it.

Change-Id: Ifc97301d26cbae4ed0aafff4d2edc398806e03f2
Bug-Url: https://bugzilla.redhat.com/show_bug.cgi?id=1081621
Signed-off-by: Donn Seeley <donn.seeley@windriver.com>
Signed-off-by: Mooli Tayer <mtayer@redhat.com>
Reviewed-on: http://gerrit.ovirt.org/26255
Reviewed-by: Zhou Zheng Sheng <zhshzhou@linux.vnet.ibm.com>
Reviewed-by: Dan Kenigsberg <danken@redhat.com>
Reviewed-on: http://gerrit.ovirt.org/26573
Reviewed-by: Yaniv Bronhaim <ybronhei@redhat.com>