glusterfsd-mgmt: unify read and write tests

1. Both read and write tests required writing first. Either just
writing (write test) or write and then read (read test).
So the code is now unified.
2. There's no reason to read zeros from /dev/zero. Just use a
CALLOC'ed buffer.
I don't think we should read and write zeros, but I did not change
the code yet (I think compression and/or dedup will offset results)

It appears neither read-perf nor write-perf were tested, so added
basic tests for them.

Change-Id: I24b1f249fa0335ed652a8982e99c0687d940230e
updates: bz#1193929
Signed-off-by: Yaniv Kaul <ykaul@redhat.com>

0 files changed, 0 insertions, 0 deletions