fix: some issues detected by linter (#96)

Author: spacewander

src/http/ngx_http_wasm_api.c

@@ -632,6 +632,10 @@ proxy_get_configuration(int32_t addr, int32_t size_addr)
 
     log = ngx_http_wasm_get_log();
     conf = ngx_http_wasm_get_conf();
+    if (conf == NULL) {
+        return PROXY_RESULT_NOT_FOUND;
+    }
+
     data = conf->data;
     len = conf->len;
 
@@ -1422,7 +1426,7 @@ proxy_http_call(int32_t up_data, int32_t up_size,
     ngx_log_t          *log;
     ngx_url_t           url;
 
-    r = ngx_http_wasm_get_req();
+    must_get_req(r);
     log = r->connection->log;
 
     if (!ngx_http_wasm_is_yieldable(r)) {

src/vm/wasmtime.c

@@ -140,7 +140,8 @@ ngx_wasm_wasmtime_load(const char *bytecode, size_t size)
     wasmtime_extern_t             item;
 
     error = wasmtime_module_new(vm_engine, (const uint8_t*) bytecode, size, &module);
-    if (module == NULL) {
+    if (error != NULL) {
+        ngx_wasm_wasmtime_report_error(ngx_cycle->log, "failed to new module: ", error, NULL);
         return NULL;
     }