size_to_str() can return a size like "4.24 MiB", with a single digit
integer part and two fractional digits. This is eight characters, but
commit b39847a5 changed the format string to only reserve seven
characters for the column.

This can result in unaligned columns, which in turn changes the output of
iotests case 267 because exceeding the column size defeats the attempt
to filter the size out of the output (observed with the ppc64 emulator).
The resulting change is only a whitespace change, but since commit
f203080b this is enough for iotests to consider the test failed.

Taking a character away from the tag name column and adding it to the VM
size column doesn't change anything in the common case (the tag name is
left justified, the VM size is right justified), but fixes this case.

Fixes: b39847a5
Signed-off-by: Kevin Wolf <kwolf@redhat.com>
Message-Id: <20210202155911.179865-1-kwolf@redhat.com>
Reviewed-by: Eric Blake <eblake@redhat.com>
Signed-off-by: Kevin Wolf <kwolf@redhat.com>