s3 rpc_client: Fix Asan stack use after scope

Fixes Asan error:

==1924==ERROR: AddressSanitizer: stack-use-after-scope on address
    0x7ffe63f873d0 at pc 0x7fb99dae1733 bp 0x7ffe63f86a00 sp 0x7ffe63f861a8
READ of size 24 at 0x7ffe63f873d0 thread T0
    #0 0x7fb99dae1732  (/usr/lib/x86_64-linux-gnu/libasan.so.4+0x79732)
    #1 0x7fb99cfe5549 in memcpy
        /usr/include/x86_64-linux-gnu/bits/string_fortified.h:34
    #2 0x7fb99cfe5549 in ndr_push_bytes
        ../../librpc/ndr/ndr_basic.c:729
    #3 0x7fb99cfe5646 in ndr_push_array_uint8
        ../../librpc/ndr/ndr_basic.c:754
    #4 0x7fb99a69dd1b in ndr_push_netr_ChallengeResponse
        librpc/gen_ndr/ndr_netlogon.c:462
    #5 0x7fb99a6c5fab in ndr_push_netr_NetworkInfo
        librpc/gen_ndr/ndr_netlogon.c:556
    #6 0x7fb99a6c749d in ndr_push_netr_LogonLevel
         librpc/gen_ndr/ndr_netlogon.c:783
    #7 0x7fb99a7222de in ndr_push_netr_LogonSamLogonEx
         librpc/gen_ndr/ndr_netlogon.c:16547
    #8 0x7fb99c982c97 in dcerpc_binding_handle_call_send
         ../../librpc/rpc/binding_handle.c:416

Bug: https://bugzilla.samba.org/show_bug.cgi?id=13936

Signed-off-by: Gary Lockyer <gary@catalyst.net.nz>
Reviewed-by: Andrew Bartlett <abartlet@samba.org>

Autobuild-User(master): Andrew Bartlett <abartlet@samba.org>
Autobuild-Date(master): Fri May 10 10:02:21 UTC 2019 on sn-devel-184

source3/rpc_client/cli_netlogon.c

@@ -472,6 +472,13 @@ NTSTATUS rpccli_netlogon_password_logon(
 	union netr_Validation *validation = NULL;
 	char *workstation_slash = NULL;
 
+	unsigned char local_nt_response[24];
+	unsigned char local_lm_response[24];
+	struct samr_Password lmpassword = {.hash = {0}};
+	struct samr_Password ntpassword = {.hash = {0}};
+	struct netr_ChallengeResponse lm = {0};
+	struct netr_ChallengeResponse nt = {0};
+
 	logon = talloc_zero(frame, union netr_LogonLevel);
 	if (logon == NULL) {
 		TALLOC_FREE(frame);
@@ -496,8 +503,6 @@ NTSTATUS rpccli_netlogon_password_logon(
 
 		struct netr_PasswordInfo *password_info;
 
-		struct samr_Password lmpassword;
-		struct samr_Password ntpassword;
 
 		password_info = talloc_zero(frame, struct netr_PasswordInfo);
 		if (password_info == NULL) {
@@ -524,10 +529,6 @@ NTSTATUS rpccli_netlogon_password_logon(
 	case NetlogonNetworkTransitiveInformation: {
 		struct netr_NetworkInfo *network_info;
 		uint8_t chal[8];
-		unsigned char local_lm_response[24];
-		unsigned char local_nt_response[24];
-		struct netr_ChallengeResponse lm;
-		struct netr_ChallengeResponse nt;
 
 		ZERO_STRUCT(lm);
 		ZERO_STRUCT(nt);