s4:torture:smb2: fix 'Use of uninitialised value of size 8' valgrind error.

s4:torture:smb2: fix 'Use of uninitialised value of size 8' valgrind error.

smbtorture test smb2.streams.sharemodes.sharemodes generates the following valgrind
trace

==16980== Use of uninitialised value of size 8
==16980==    at 0x8F005C2: _samba_rijndaelEncrypt (rijndael-alg-fst.c:957)
==16980==    by 0x8EFF24C: samba_AES_encrypt (aes.c:60)
==16980==    by 0x8F01A74: aes_cmac_128_update (aes_cmac_128.c:151)
==16980==    by 0xB0D11B7: smb2_signing_sign_pdu (smb2_signing.c:74)
==16980==    by 0xB0D984A: smb2cli_req_compound_submit (smbXcli_base.c:3062)
==16980==    by 0x5AFD5F5: smb2_transport_send (transport.c:237)
==16980==    by 0x5B030F3: smb2_close_send (close.c:42)
==16980==    by 0x5B0358A: smb2_close (close.c:78)
==16980==    by 0x5B087B3: smb2_util_close (util.c:40)
==16980==    by 0x51B4F3: test_stream_sharemodes (streams.c:557)
==16980==    by 0x48B452: wrap_simple_1smb2_test (smb2.c:52)
==16980==    by 0x955368F: internal_torture_run_test (torture.c:442)
==16980==    by 0x9553A6B: torture_run_test_restricted (torture.c:542)
==16980==    by 0x26013F: run_matching (smbtorture.c:110)
==16980==    by 0x260001: run_matching (smbtorture.c:95)
==16980==    by 0x260001: run_matching (smbtorture.c:95)
==16980==    by 0x260260: torture_run_named_tests (smbtorture.c:143)
==16980==    by 0x261EDF: main (smbtorture.c:665)
==16980==
==16980== Use of uninitialised value of size 8
==16980==    at 0x8F005DE: _samba_rijndaelEncrypt (rijndael-alg-fst.c:958)
==16980==    by 0x8EFF24C: samba_AES_encrypt (aes.c:60)
==16980==    by 0x8F01A74: aes_cmac_128_update (aes_cmac_128.c:151)
==16980==    by 0xB0D11B7: smb2_signing_sign_pdu (smb2_signing.c:74)
==16980==    by 0xB0D984A: smb2cli_req_compound_submit (smbXcli_base.c:3062)
==16980==    by 0x5AFD5F5: smb2_transport_send (transport.c:237)
==16980==    by 0x5B030F3: smb2_close_send (close.c:42)
==16980==    by 0x5B0358A: smb2_close (close.c:78)
==16980==    by 0x5B087B3: smb2_util_close (util.c:40)
==16980==    by 0x51B4F3: test_stream_sharemodes (streams.c:557)
==16980==    by 0x48B452: wrap_simple_1smb2_test (smb2.c:52)
==16980==    by 0x955368F: internal_torture_run_test (torture.c:442)
==16980==    by 0x9553A6B: torture_run_test_restricted (torture.c:542)
==16980==    by 0x26013F: run_matching (smbtorture.c:110)
==16980==    by 0x260001: run_matching (smbtorture.c:95)
==16980==    by 0x260001: run_matching (smbtorture.c:95)
==16980==    by 0x260260: torture_run_named_tests (smbtorture.c:143)
==16980==    by 0x261EDF: main (smbtorture.c:665)
==16980==

Signed-off-by: Noel Power <noel.power@suse.com>
Reviewed-by: Volker Lendecke <vl@samba.org>
Reviewed-by: Andreas Schneider <asn@samba.org>