tweak: fixed some warnings from the clang static code analyzer.

Author: agentzh

src/ngx_http_lua_semaphore.c

@@ -86,6 +86,8 @@ ngx_http_lua_alloc_sema(void)
     lmcf = ngx_http_cycle_get_module_main_conf(ngx_cycle,
                                                ngx_http_lua_module);
 
+    ngx_http_lua_assert(lmcf != NULL);
+
     mm = lmcf->sema_mm;
 
     if (!ngx_queue_empty(&mm->free_queue)) {
@@ -172,6 +174,8 @@ ngx_http_lua_sema_mm_cleanup(void *data)
         sem = ngx_queue_data(q, ngx_http_lua_sema_t, chain);
         block = sem->block;
 
+        ngx_http_lua_assert(block != NULL);
+
         if (block->used == 0) {
             iter = (ngx_http_lua_sema_t *) (block + 1);
 

src/ngx_http_lua_util.c

@@ -269,7 +269,6 @@ ngx_http_lua_new_state(lua_State *parent_vm, ngx_cycle_t *cycle,
 
         lua_pushliteral(L, LUA_DEFAULT_PATH ";"); /* package default */
         lua_getfield(L, -2, "path"); /* package default old */
-        old_path = lua_tolstring(L, -1, &old_path_len);
         lua_concat(L, 2); /* package new */
         lua_setfield(L, -2, "path"); /* package */
 #endif