iotests: Fix 104 for NBD

_make_test_img sets up an NBD server, _cleanup_test_img shuts it down;
thus, _cleanup_test_img has to be called before _make_test_img is
invoked another time.

Furthermore, the pipe through _filter_test_img was unnecessary;
_make_test_img already takes care of that.

And finally, a filter is added to _filter_img_info to replace
"nbd://127.0.0.1:10810" by "TEST_DIR/t.IMGFMT", since the former is the
way to express the full image path (normally the latter) for NBD tests.

Signed-off-by: Max Reitz <mreitz@redhat.com>
Reviewed-by: Paolo Bonzini <pbonzini@redhat.com>
Signed-off-by: Kevin Wolf <kwolf@redhat.com>

tests/qemu-iotests/104

@@ -28,11 +28,7 @@ here=`pwd`
 tmp=/tmp/$$
 status=1	# failure is the default!
 
-_cleanup()
-{
-	_cleanup_test_img
-}
-trap "_cleanup; exit \$status" 0 1 2 3 15
+trap "exit \$status" 0 1 2 3 15
 
 # get standard environment, filters and checks
 . ./common.rc
@@ -47,8 +43,9 @@ echo
 image_sizes="1024 1234"
 
 for s in $image_sizes; do
-    _make_test_img $s | _filter_img_create
+    _make_test_img $s
     _img_info | _filter_img_info
+    _cleanup_test_img
 done
 
 # success, all done

tests/qemu-iotests/common.filter

@@ -200,6 +200,7 @@ _filter_img_info()
     sed -e "s#$IMGPROTO:$TEST_DIR#TEST_DIR#g" \
         -e "s#$TEST_DIR#TEST_DIR#g" \
         -e "s#$IMGFMT#IMGFMT#g" \
+        -e 's#nbd://127.0.0.1:10810$#TEST_DIR/t.IMGFMT#g' \
         -e "/encrypted: yes/d" \
         -e "/cluster_size: [0-9]\\+/d" \
         -e "/table_size: [0-9]\\+/d" \