block/ssh: Implement .bdrv_refresh_filename()

block/ssh: Implement .bdrv_refresh_filename()

This requires some changes to keep iotests 104 and 207 working.

qemu-img info in 104 will now return a filename including the user name
and the port, which need to be filtered by adjusting REMOTE_TEST_DIR in
common.rc.  This additional information has to be marked optional,
however (which is simple as REMOTE_TEST_DIR is a regex), because
otherwise 197 and 215 would fail: They use it (indirectly) to filter
qemu-img create output which contains a backing filename they have
passed to it -- which probably does not contain a user name or port
number.

The problem in 207 is a nice one to have: qemu-img info used to return
json:{} filenames, but with this patch it returns nice plain ones.  We
now need to adjust the filtering to hide the user name (and port number
while we are at it).  The simplest way to do this is to include both in
iotests.remote_filename() so that bdrv_refresh_filename() will not
change it, and then iotests.img_info_log() will filter it correctly
automatically.

Signed-off-by: Max Reitz <mreitz@redhat.com>
Tested-by: Richard W.M. Jones <rjones@redhat.com>
Message-id: 20190225190828.17726-2-mreitz@redhat.com
Signed-off-by: Max Reitz <mreitz@redhat.com>