Regression test portability: ec.t

This test unmount/remount the filesystem to invalidate cache,
but this leads to timing problems on NetBSD. We can work them
around without sleeping by remounting on another mount point.

BUG: 1129939
Change-Id: I10b3183e5e715053de162a6980af188710b607bb
Signed-off-by: Emmanuel Dreyfus <manu@netbsd.org>
Reviewed-on: http://review.gluster.org/9285
Tested-by: Gluster Build System <jenkins@build.gluster.com>
Reviewed-by: Xavier Hernandez <xhernandez@datalab.es>