block/rbd: fix memory leak in qemu_rbd_co_create_opts()

block/rbd: fix memory leak in qemu_rbd_co_create_opts()

When we allocate 'q_namespace', we forgot to set 'has_q_namespace'
to true. This can cause several issues, including a memory leak,
since qapi_free_BlockdevCreateOptions() does not deallocate that
memory, as reported by valgrind:

  13 bytes in 1 blocks are definitely lost in loss record 7 of 96
     at 0x4839809: malloc (vg_replace_malloc.c:307)
     by 0x48CEBB8: g_malloc (in /usr/lib64/libglib-2.0.so.0.6600.8)
     by 0x48E3FE3: g_strdup (in /usr/lib64/libglib-2.0.so.0.6600.8)
     by 0x180010: qemu_rbd_co_create_opts (rbd.c:446)
     by 0x1AE72C: bdrv_create_co_entry (block.c:492)
     by 0x241902: coroutine_trampoline (coroutine-ucontext.c:173)
     by 0x57530AF: ??? (in /usr/lib64/libc-2.32.so)
     by 0x1FFEFFFA6F: ???

Fix setting 'has_q_namespace' to true when we allocate 'q_namespace'.

Fixes: 19ae9ae014 ("block/rbd: Add support for ceph namespaces")
Signed-off-by: Stefano Garzarella <sgarzare@redhat.com>
Message-Id: <20210329150129.121182-3-sgarzare@redhat.com>
Reviewed-by: Markus Armbruster <armbru@redhat.com>
Reviewed-by: Max Reitz <mreitz@redhat.com>
Signed-off-by: Kevin Wolf <kwolf@redhat.com>