delete useless statement

src/os/unix/ngx_posix_init.c

diff --git a/src/os/unix/ngx_posix_init.c b/src/os/unix/ngx_posix_init.c
index b38a810..f216144 100644
--- a/src/os/unix/ngx_posix_init.c
+++ b/src/os/unix/ngx_posix_init.c
@@ -44,8 +44,6 @@
     ngx_pagesize = getpagesize();
     ngx_cacheline_size = NGX_CPU_CACHE_LINE;
 
-    n = ngx_pagesize;
-
     for (n = ngx_pagesize; n >>= 1; ngx_pagesize_shift++) { /* void */ }
 
     if (ngx_ncpu == 0) {