bugfix: bugs in the error handling for pure C API functions for shared dict. thanks Xiaochen Wang for the patch in openresty#365.

Author: agentzh

src/ngx_http_lua_shdict.c

@@ -1270,6 +1270,7 @@ ngx_http_lua_shared_dict_get(ngx_shm_zone_t *zone, u_char *key_data,
         if (value->value.s.data == NULL || value->value.s.len == 0) {
             ngx_log_error(NGX_LOG_ERR, ngx_cycle->log, 0, "no string buffer "
                           "initialized");
+            ngx_shmtx_unlock(&ctx->shpool->mutex);
             return NGX_ERROR;
         }
 
@@ -1721,6 +1722,7 @@ ngx_http_lua_ffi_shdict_get(ngx_shm_zone_t *zone, u_char *key,
                       "bad value type found for key %*s in "
                       "shared_dict %V: %d", key_len, key, &name,
                       *value_type);
+        return NGX_ERROR;
     }
 
     *user_flags = sd->user_flags;