block: Fix leak in send_qmp_error_event

block: Fix leak in send_qmp_error_event

ASAN detected a leak when running the ahci-test
/ahci/io/dma/lba28/retry:

Direct leak of 35 byte(s) in 1 object(s) allocated from:
    #0 in malloc
    #1 in __vasprintf_internal
    #2 in vasprintf
    #3 in g_vasprintf
    #4 in g_strdup_vprintf
    #5 in g_strdup_printf
    #6 in object_get_canonical_path ../qom/object.c:2096:19
    #7 in blk_get_attached_dev_id_or_path ../block/block-backend.c:1033:12
    #8 in blk_get_attached_dev_path ../block/block-backend.c:1047:12
    #9 in send_qmp_error_event ../block/block-backend.c:2140:36
    #10 in blk_error_action ../block/block-backend.c:2172:9
    #11 in ide_handle_rw_error ../hw/ide/core.c:875:5
    #12 in ide_dma_cb ../hw/ide/core.c:894:13
    #13 in dma_complete ../system/dma-helpers.c:107:9
    #14 in dma_blk_cb ../system/dma-helpers.c:129:9
    #15 in blk_aio_complete ../block/block-backend.c:1552:9
    #16 in blk_aio_write_entry ../block/block-backend.c:1619:5
    #17 in coroutine_trampoline ../util/coroutine-ucontext.c:175:9

Plug the leak by freeing the device path string.

Signed-off-by: Fabiano Rosas <farosas@suse.de>
Reviewed-by: Philippe Mathieu-Daudé <philmd@linaro.org>
Message-ID: <20241111145214.8261-1-farosas@suse.de>
[PMD: Use g_autofree]
Signed-off-by: Philippe Mathieu-Daudé <philmd@linaro.org>
Message-ID: <20241111170333.43833-3-philmd@linaro.org>
Signed-off-by: Kevin Wolf <kwolf@redhat.com>