remote: Fix a segfault in remoteDomainCreateWithFlags

Valgrind defects memory error:

==16759== 1 errors in context 1 of 8:
==16759== Invalid free() / delete / delete[] / realloc()
==16759==    at 0x4A074C4: free (in /usr/lib64/valgrind/vgpreload_memcheck-amd64-linux.so)
==16759==    by 0x83CD329: xdr_string (in /usr/lib64/libc-2.17.so)
==16759==    by 0x4D93E4D: xdr_remote_nonnull_string (remote_protocol.c:31)
==16759==    by 0x4D94350: xdr_remote_nonnull_domain (remote_protocol.c:58)
==16759==    by 0x4D976C8: xdr_remote_domain_create_with_flags_ret (remote_protocol.c:1762)
==16759==    by 0x83CC734: xdr_free (in /usr/lib64/libc-2.17.so)
==16759==    by 0x4D7F1E0: remoteDomainCreateWithFlags (remote_driver.c:2441)
==16759==    by 0x4D4BF17: virDomainCreateWithFlags (libvirt.c:9499)
==16759==    by 0x13127A: cmdStart (virsh-domain.c:3376)
==16759==    by 0x12BF83: vshCommandRun (virsh.c:1751)
==16759==    by 0x126FFB: main (virsh.c:3205)
==16759==  Address 0xe1394a0 is not stack'd, malloc'd or (recently) free'd

==16759== 1 errors in context 2 of 8:
==16759== Conditional jump or move depends on uninitialised value(s)
==16759==    at 0x4A07477: free (in /usr/lib64/valgrind/vgpreload_memcheck-amd64-linux.so)
==16759==    by 0x83CD329: xdr_string (in /usr/lib64/libc-2.17.so)
==16759==    by 0x4D93E4D: xdr_remote_nonnull_string (remote_protocol.c:31)
==16759==    by 0x4D94350: xdr_remote_nonnull_domain (remote_protocol.c:58)
==16759==    by 0x4D976C8: xdr_remote_domain_create_with_flags_ret (remote_protocol.c:1762)
==16759==    by 0x83CC734: xdr_free (in /usr/lib64/libc-2.17.so)
==16759==    by 0x4D7F1E0: remoteDomainCreateWithFlags (remote_driver.c:2441)
==16759==    by 0x4D4BF17: virDomainCreateWithFlags (libvirt.c:9499)
==16759==    by 0x13127A: cmdStart (virsh-domain.c:3376)
==16759==    by 0x12BF83: vshCommandRun (virsh.c:1751)
==16759==    by 0x126FFB: main (virsh.c:3205)
==16759==  Uninitialised value was created by a stack allocation
==16759==    at 0x4D7F120: remoteDomainCreateWithFlags (remote_driver.c:2423)

How to reproduce?

# virsh start <domain> --paused

RHBZ: https://bugzilla.redhat.com/show_bug.cgi?id=994855Signed-off-by: NAlex Jia <ajia@redhat.com>
(cherry picked from commit be7a89e8)

src/remote/remote_driver.c

@@ -2431,6 +2431,7 @@ remoteDomainCreateWithFlags(virDomainPtr dom, unsigned int flags)
     make_nonnull_domain(&args.dom, dom);
     args.flags = flags;
 
+    memset(&ret, 0, sizeof(ret));
     if (call(dom->conn, priv, 0, REMOTE_PROC_DOMAIN_CREATE_WITH_FLAGS,
              (xdrproc_t)xdr_remote_domain_create_with_flags_args, (char *)&args,
              (xdrproc_t)xdr_remote_domain_create_with_flags_ret, (char *)&ret) == -1) {