doc: Moved non-relevant documentation files to legacy

Change-Id: I2d34e5a4e47cd03d301d9fd2525fb61ae997fcb8
BUG: 811311
Signed-off-by: Vijay Bellur <vbellur@redhat.com>
Reviewed-on: http://review.gluster.org/5277
Tested-by: Gluster Build System <jenkins@build.gluster.com>