Removing unused logErr parameter from execCmd

Change-Id: Ic07b3524246d8795df8accf35c9a9a82e42d8497
Signed-off-by: Yaniv Bronhaim <ybronhei@redhat.com>
Reviewed-on: http://gerrit.ovirt.org/28050
Reviewed-by: Antoni Segura Puimedon <asegurap@redhat.com>
Reviewed-by: Dan Kenigsberg <danken@redhat.com>
Reviewed-by: Nir Soffer <nsoffer@redhat.com>
Reviewed-by: Saggi Mizrahi <smizrahi@redhat.com>