govendor同步google的项目时，因为防火墙原因会导致无法访问。

root [~] govendor sync
Error: Remotes failed for:
    Failed for "google.golang.org/appengine/cloudsql" (failed to ping remote repo): unrecognized import path "google.golang.org/appengine/cloudsql"

几种方式设置代理，解决这个问题：

1. 需要在/etc/profile中设置一下代理，然后source一下

#Proxy
export http_proxy=socks5://127.0.0.1:xxxx
export https_proxy=$http_proxy
export ftp_proxy=$http_proxy
export rsync_proxy=$http_proxy
export no_proxy="localhost,127.0.0.1,localaddress,.localdomain.com"

2. 更换仓库
使用这个地址：
https://github.com/golang/appengine
Go App Engine packages http://google.golang.org/appengine

3. shell命令设置http_proxy

root [~] export http_proxy=socks5://127.0.0.1:xxxx
root [~] govendor sync
root [~] unset http_proxy