Use permalinks for the Git for Windows RCs, add 2.4.5.1

Signed-off-by: Johannes Schindelin <[email protected]>

Author: dscho

rev_news/drafts/edition-5.md

@@ -210,7 +210,8 @@ bogus format ensued.
 
 * [git-multimail](https://github.com/git-multimail/git-multimail) [1.1.0](https://github.com/git-multimail/git-multimail/releases/tag/1.1.0) was released. git-multimail is a tool to send notification emails for pushes to a git repository. It is also available in the `contrib/hooks/multimail/` directory of Git's source tree (version 1.1.0 will be distributed with Git 2.5).
 
-* [Git for Windows 2.4.4.2 Release Notes](https://github.com/git-for-windows/build-extra/blob/master/installer/ReleaseNotes.md)
+* [Git for Windows 2.4.4.2 Release Notes](https://github.com/git-for-windows/build-extra/blob/fd821c12f/installer/ReleaseNotes.md)
+* [Git for Windows 2.4.5.1 Release Notes](https://github.com/git-for-windows/build-extra/blob/125ac3d8e/installer/ReleaseNotes.md)
 * [Git 2.4.5](http://git-blame.blogspot.de/2015/06/git-245.html)
 * [Git 2.5-rc0 early preview](http://git-blame.blogspot.de/2015/06/git-25-rc0-early-preview.html)
 * [jgit 4.0.0](http://dev.eclipse.org/mhonarc/lists/jgit-dev/msg02914.html)