Fixes valgrind warning
==354193== Thread 39:
==354193== Syscall param sendmsg(msg.msg_iov[0]) points to uninitialised byte(s)
==354193== at 0xC0A146D: sendmsg (in /usr/lib/libc.so.6)
==354193== by 0x18527D: ipc_send (src/xrt/ipc/shared/ipc_utils.c:65)
==354193== by 0x157771: ipc_dispatch (ipc_server_generated.c:165)
==354193== by 0x15C88D: client_loop (src/xrt/ipc/server/ipc_server_per_client_thread.c:112)
==354193== by 0x15C60C: ipc_server_client_thread (src/xrt/ipc/server/ipc_server_per_client_thread.c:183)
==354193== by 0xC01A5C1: start_thread (in /usr/lib/libc.so.6)
==354193== by 0xC09F583: clone (in /usr/lib/libc.so.6)
==354193== Address 0xc0866afc is on thread 39's stack
==354193== in frame #2, created by ipc_dispatch (ipc_server_generated.c:23)
==354193== Uninitialised value was created by a stack allocation
==354193== at 0x15F830: xrt_gfx_provider_create_system (src/xrt/compositor/main/comp_compositor.c:1118)
Fixes validation error when calling render_buffer_init_exportable
VUID-vkBindBufferMemory-memory-02726(ERROR / SPEC): msgNum: -168767885 - Validation Error: [ VUID-vkBindBufferMemory-memory-02726 ] Object 0: handle = 0xe88693000000000c, type = VK_OBJECT_TYPE_BUFFER; Object 1: handle = 0xcad092000000000d, type = VK_OBJECT_TYPE_DEVICE_MEMORY; | MessageID = 0xf5f0ce73 | vkBindBufferMemory(): The VkDeviceMemory (VkDeviceMemory 0xcad092000000000d[]) has an external handleType of VK_EXTERNAL_MEMORY_HANDLE_TYPE_OPAQUE_FD_BIT which does not include at least one handle from VkBuffer (VkBuffer 0xe88693000000000c[]) handleType Unhandled VkExternalMemoryHandleTypeFlagBits. The Vulkan spec states: If the value of VkExportMemoryAllocateInfo::handleTypes used to allocate memory is not 0, it must include at least one of the handles set in VkExternalMemoryBufferCreateInfo::handleTypes when buffer was created (https://www.khronos.org/registry/vulkan/specs/1.3-extensions/html/vkspec.html#VUID-vkBindBufferMemory-memory-02726)
Objects: 2
[0] 0xe88693000000000c, type: 9, name: NULL
[1] 0xcad092000000000d, type: 8, name: NULL
