Change lvm filter use of regular expression to 'replace \x'

Change-Id: Ia5428d3d8b1d0b10b083b663b12d3a6ceb7e3e69
Bug-Url: https://bugzilla.redhat.com/show_bug.cgi?id=908776
Signed-off-by: Yeela Kaplan <ykaplan@redhat.com>
Reviewed-on: http://gerrit.ovirt.org/11852
Reviewed-by: Ayal Baron <abaron@redhat.com>