thin_ls can corrupt thin pools with specific kernel versions

[derekwaynecarr]

using thin_ls can corrupt thin pools with specific kernel versions due to kernel bug.

• cadvisor should not call thin_ls on kernels < 4.4
• unless those are kernels that have been specifically fixed in an earlier version:
  • i.e. on RHEL greater than or equal to kernel-3.10.0-366.el7

See: https://bugzilla.redhat.com/show_bug.cgi?id=1363776

/cc @pmorie @ncdc @vishh @timstclair

[derekwaynecarr]

/cc @eparis