talloc: ASAN fix for test_pool_nest

talloc: ASAN fix for test_pool_nest

Direct leak of 96 byte(s) in 1 object(s) allocated from:
    #0 0x7f06393dfc08 in __interceptor_malloc (/lib64/libasan.so.5+0xefc08)
    #1 0x7f06392d0c45 in __talloc_with_prefix ../../talloc.c:782
    #2 0x7f06392d0c45 in __talloc ../../talloc.c:824
    #3 0x7f06392d0c45 in _talloc_named_const ../../talloc.c:981
    #4 0x7f06392d0c45 in talloc_named_const ../../talloc.c:1748
    #5 0x40901e in test_pool_nest ../../testsuite.c:1451
    #6 0x40901e in torture_local_talloc ../../testsuite.c:2096
    #7 0x402603 in main ../../testsuite_main.c:32
    #8 0x7f063908a412 in __libc_start_main (/lib64/libc.so.6+0x24412)

Signed-off-by: Swen Schillig <swen@linux.ibm.com>
Reviewed-by: Andrew Bartlett <abartlet@samba.org>
Reviewed-by: Matthias Dieter Wallnöfer <mdw@samba.org>