tests: attr/xattr.h doesn't exist without libattr-devel fix it

Use sys/xattr.h - glibc provided rather than external libs

Change-Id: Iacf80c1089f11a5a9b46d24e2a62e41fa0c4f5ae
BUG: 1084422
Signed-off-by: Harshavardhana <harsha@harshavardhana.net>
Reviewed-on: http://review.gluster.org/8146
Tested-by: Gluster Build System <jenkins@build.gluster.com>
Reviewed-by: M S Vishwanath Bhat <vbhat@redhat.com>