tests/qemu-iotests: Remove test 259 from the "auto" group

Tests in the "auto" group should support qcow2 so that they can
be run during "make check-block". Test 259 only supports "raw", so
it currently always gets skipped when running "make check-block".
Let's skip this unnecessary step and remove it from the auto group.

Signed-off-by: Thomas Huth <thuth@redhat.com>
Message-Id: <20210215103835.1129145-1-thuth@redhat.com>
Signed-off-by: Kevin Wolf <kwolf@redhat.com>
diff --git a/tests/qemu-iotests/259 b/tests/qemu-iotests/259
index 76cde42..1b15e8f 100755
--- a/tests/qemu-iotests/259
+++ b/tests/qemu-iotests/259
@@ -1,5 +1,5 @@
 #!/usr/bin/env bash
-# group: rw auto quick
+# group: rw quick
 #
 # Test generic image creation fallback (by using NBD)
 #