Fixed "changing binary" when reaper is not init. On some systems, it's possible that reaper of orphaned processes is set to something other than "init" process. On such systems, the changing binary procedure did not work. The fix is to check if PPID has changed, instead of assuming it's always 1 for orphaned processes.

--- a/src/core/nginx.c
+++ b/src/core/nginx.c
@@ -228,6 +228,7 @@ main(int argc, char *const *argv)
 #endif
 
     ngx_pid = ngx_getpid();
+    ngx_parent = ngx_getppid();
 
     log = ngx_log_init(ngx_prefix);
     if (log == NULL) {