qemu-iotests: remove unused variable 'here'

qemu-iotests: remove unused variable 'here'

Running
git grep '\$here' tests/qemu-iotests

has 0 hits, which means we are setting a variable that has
no use.  It appears that commit e8f8624d removed the last
use.  So execute the following cmd to remove all of
the 'here=...' lines as dead code.

sed -i '/^here=/d' $(git grep -l '^here=' tests/qemu-iotests)

Cc: kwolf@redhat.com
Cc: mreitz@redhat.com
Cc: eblake@redhat.com
Suggested-by: Eric Blake <eblake@redhat.com>
Signed-off-by: Mao Zhongyi <maozhongyi@cmss.chinamobile.com>
Message-Id: <20181024094051.4470-3-maozhongyi@cmss.chinamobile.com>
Reviewed-by: Eric Blake <eblake@redhat.com>
[eblake: touch up commit message, reorder series, rebase to master]
Signed-off-by: Eric Blake <eblake@redhat.com>