vulkan: apply 138.0..v138.2 changes to api file

Change-Id: Icdadba710a2990e26ca13472f0efad55f66a403e
(cherry picked from commit 38347619f9d99bb4756ccde83389242e0f3d8986)
diff --git a/vulkan/api/templates/vulkan_h.tmpl b/vulkan/api/templates/vulkan_h.tmpl
index df0ae6f..6747147 100644
--- a/vulkan/api/templates/vulkan_h.tmpl
+++ b/vulkan/api/templates/vulkan_h.tmpl
@@ -70,8 +70,8 @@
 #endif
 #define VK_DEFINE_NONDISP_HANDLE(obj)                                              \
     struct obj {                                                                   \
-        obj() {}                                                                   \
-        obj(uint64_t x) { handle = x; }                                            \
+        obj() : handle(0) { }                                                      \
+        obj(uint64_t x) : handle(x) { }                                            \
         obj& operator=(uint64_t x) {                                               \
             handle = x;                                                            \
             return *this;                                                          \