nx-X11/programs/Xserver/hw/nxagent/Display.c: use new ReconnectTolerance nxagentOption value in nxagentCheckForDepthsCompatibility() and modify behavior based on this value.

Recognized values:
  - Strict means that the number of old and new depths must
    match exactly and every old depth value must be
    available in the new depth array.
  - Safe means that the number of depths might diverge,
    but all former depth must also be included in the
    new depth array. This is recommended, because
    it allows clients with more depths to still
    connect, but not lose functionality.
  - Risky means that the new depths array is allowed to be
    smaller than the old depths array, but at least
    one depth value must be included in both.
    This is potentially unsafe.
  - Bypass or higher means that all of these checks are
    essentially deactivated. This is a very bad idea.

Note that the default ReconnectTolerance value is still Strict.