s3:passdb: Do not leak memory in pdb_tdb

s3:passdb: Do not leak memory in pdb_tdb

==19938==ERROR: LeakSanitizer: detected memory leaks

Direct leak of 77 byte(s) in 1 object(s) allocated from:
    #0 0x7f7d482841f8 in strdup (/lib64/libasan.so.8+0x841f8) (BuildId: 3e1694ad218c99a8b1b69231666a27df63cf19d0)
    #1 0x7f7d47204846  (bin/shared/libsamba-util.so.0+0x4c846) (BuildId: 43b084eb9013442ac68eb1fc17649f142cbb0f94)
    #2 0x7f7d40b1d97a in pdb_init_tdbsam ../../source3/passdb/pdb_tdb.c:1361
    #3 0x7f7d4715f266  (bin/shared/libsamba-passdb.so.0+0x76266) (BuildId: 13d2858e2217592a22a4ee9203fef759d52df733)
    #4 0x7f7d4715f57a  (bin/shared/libsamba-passdb.so.0+0x7657a) (BuildId: 13d2858e2217592a22a4ee9203fef759d52df733)
    #5 0x7f7d47163700  (bin/shared/libsamba-passdb.so.0+0x7a700) (BuildId: 13d2858e2217592a22a4ee9203fef759d52df733)
    #6 0x55a9177d3853 in main ../../source3/smbd/server.c:1928
    #7 0x7f7d434281af in __libc_start_call_main ../sysdeps/nptl/libc_start_call_main.h:58

Signed-off-by: Andreas Schneider <asn@samba.org>
Reviewed-by: Volker Lendecke <vl@samba.org>