vdsmd.init: disable libvirt connection keepalives

Libvirt now has keepalives enabledby default (see bug 832081), but
they should be disabled until vdsm can make use of them (bug 949192).

The main problem remaining is that certain libvirt versions (notably
0.10.2-18.el6.x86_64) don't behave well when using keepalives: the
connection can be closed if the system is under load, causing spurious
vdsm problems that wouldn't be present if keepalives weren't in use.

The libvirt bug has been subsequently fixed, but until a newer libvirt
can be required, we shouldn't rely on the corrected behavior.

Change-Id: I632d02f12481911c4ceb6477c42c3b66de47d0c9
Bug-Url: https://bugzilla.redhat.com/834041
Signed-off-by: Greg Padgett <gpadgett@redhat.com>
Reviewed-on: http://gerrit.ovirt.org/14010
Reviewed-by: Yaniv Bronhaim <ybronhei@redhat.com>
Reviewed-by: Dan Kenigsberg <danken@redhat.com>
Tested-by: Yaniv Bronhaim <ybronhei@redhat.com>