Regression test portability: self-heald.t

Fix portability problems in updated self-heald.t:
- Use the k suffit in dd(1) bs argument instead of less portable M and K
- Error message for disconnected bricks in NetBSD is "Socket is not connected"
- On touch d/a while bricks are down, NetBSD updates d ctime/mtime even
  on bricks where a is not present, resulting in a different to-be-healed
  count than on Linux. We now tes both values. If NetBSD behavior is a bug,
  it is not in the heal process and should be tested somewhere else.

This also requires fixes in heal process: http://review.gluster.org/8936

BUG: 1129939
Change-Id: Ibda1902a8fd64aa7cc5202744adca825e6b251c9
Signed-off-by: Emmanuel Dreyfus <manu@netbsd.org>
Reviewed-on: http://review.gluster.org/8968
Reviewed-by: Kaleb KEITHLEY <kkeithle@redhat.com>
Reviewed-by: Pranith Kumar Karampuri <pkarampu@redhat.com>
Reviewed-by: Vijay Bellur <vbellur@redhat.com>