iotests: s/qocw2/qcow2/

Probably due to blind copy-pasting, we have several instances of "qocw2"
in our iotests.  Fix them.

Reported-by: Maxim Levitsky <mlevitsk@redhat.com>
Signed-off-by: Max Reitz <mreitz@redhat.com>
Message-id: 20191107163708.833192-2-mreitz@redhat.com
Reviewed-by: Eric Blake <eblake@redhat.com>
Reviewed-by: Maxim Levitsky <mlevitsk@redhat.com>
Signed-off-by: Max Reitz <mreitz@redhat.com>
diff --git a/tests/qemu-iotests/060 b/tests/qemu-iotests/060
index d96f17a..7439be8 100755
--- a/tests/qemu-iotests/060
+++ b/tests/qemu-iotests/060
@@ -44,7 +44,7 @@
 . ./common.rc
 . ./common.filter
 
-# This tests qocw2-specific low-level functionality
+# This tests qcow2-specific low-level functionality
 _supported_fmt qcow2
 _supported_proto file
 _supported_os Linux