Core: properly initialized written bytes counter in memory log.

src/core/ngx_log.c

diff --git a/src/core/ngx_log.c b/src/core/ngx_log.c
index 2aea374..0893871 100644
--- a/src/core/ngx_log.c
+++ b/src/core/ngx_log.c
@@ -609,7 +609,7 @@
             return NGX_CONF_ERROR;
         }
 
-        buf = ngx_palloc(cf->pool, sizeof(ngx_log_memory_buf_t));
+        buf = ngx_pcalloc(cf->pool, sizeof(ngx_log_memory_buf_t));
         if (buf == NULL) {
             return NGX_CONF_ERROR;
         }