go.tools/blog: replace "\\" with "/" in path string to be compatible with windows platform
go.tools/blog: replace "\\" with "/" in path string to be compatible with windows platform

Fixes Issue 6539

The problem happens on my win7,
for example, the path is "/content\\foo.article".
It leads to the wrong link in generated html page.
So I think we should replace all"\\" with "/" in path string at first.

R=golang-dev, dsymonds, mirtchovski, dave, adg, alex.brainman
CC=golang-dev
https://codereview.appspot.com/14023043

Committer: Andrew Gerrand <395a7d33bec8475c9b83b7d440f141bcbd994aa5@golang.org>

d0f/go-zh.tools,8limbs/gotools,webfd/go-zh.tools,webfd/go-zh.tools,bryanxu/go-zh.tools,d0f/go-zh.tools,8limbs/gotools,skyportsystems/go.tools,webfd/go-zh.tools,8limbs/gotools,webfd/go-zh.tools,skyportsystems/go.tools,d0f/go-zh.tools,bryanxu/go-zh.tools,bryanxu/go-zh.tools,skyportsystems/go.tools,bryanxu/go-zh.tools,skyportsystems/go.tools,skyportsystems/go.tools,webfd/go-zh.tools,d0f/go-zh.tools,d0f/go-zh.tools,bryanxu/go-zh.tools