protocol/client: Log ENOENT and ENODATA messages to debug.

Change-Id: I6f8ccf1650ff74e46e5a93a6701d4e694118b273
BUG: 1120136
Signed-off-by: Raghavendra Talur <rtalur@redhat.com>
Reviewed-on: http://review.gluster.org/8315
Reviewed-by: Krishnan Parthasarathi <kparthas@redhat.com>
Tested-by: Gluster Build System <jenkins@build.gluster.com>
Reviewed-by: Vijay Bellur <vbellur@redhat.com>