Fixes issue 2114: Rebase touches lots of working dir files

Fixes issue 2114: Rebase touches lots of working dir files
Step 1
![tgit-2114-1](https://f.cloud.github.com/assets/2804967/2208819/36122594-9984-11e3-86de-31c9a626ae98.png)
Step 2: right click commit cmn/safe-commit ->,Rebase
![tgit-2114-6](https://f.cloud.github.com/assets/2804967/2230871/d54acba4-9b08-11e3-9409-3fa0d3a19af7.png)
Step 3: click reverse button
![tgit-2114-5](https://f.cloud.github.com/assets/2804967/2230860/9c1d5982-9b08-11e3-914d-77b07feea8ff.png)