fstests: add orangefs (pvfs2) support

fstests: add orangefs (pvfs2) support

The filesystem was renamed OrangeFS from PVFS2 recently.  The mount
-t type remains pvfs2, so I have used that name throughout despite
the kernel module being named orangefs.

We've been maintaining this as a patch for quite some time.

The easiest way to use is to setup a single server installation with
multiple filesystems orangefs and scratch, put the following in
/etc/xfsqa.config, and run ./check -pvfs2 -g quick.

TEST_DIR=/mnt
TEST_DEV=tcp://server1vm:3334/orangefs
SCRATCH_MNT=/scratch
SCRATCH_DEV=tcp://server1vm:3334/scratch

Signed-off-by: Martin Brandenburg <martin@omnibond.com>
Reviewed-by: Eryu Guan <eguan@redhat.com>
Signed-off-by: Eryu Guan <eguan@redhat.com>