Add 'revert' example to git-drover docs.

Add 'revert' example to git-drover docs.

TBR=iannucci@chromium.org

Committed: http://src.chromium.org/viewvc/chrome?view=rev&revision=291840

[Michael Moss, 2014-09-05 23:11:59]

On 2014/09/05 23:10:31, Michael Moss wrote:

This is so I can get rid of the mostly redundant
https://sites.google.com/a/chromium.org/dev/developers/how-tos/drover and just
point it to the git-drover page.

[Michael Moss, 2014-09-06 00:03:41]

On 2014/09/05 23:11:59, Michael Moss wrote:
> On 2014/09/05 23:10:31, Michael Moss wrote:
> 
> This is so I can get rid of the mostly redundant
> https://sites.google.com/a/chromium.org/dev/developers/how-tos/drover and just
> point it to the git-drover page.

Pushed new man page and updated the wiki.

[Michael Moss, 2014-09-06 00:03:48]

The CQ bit was checked by mmoss@chromium.org

[commit-bot: I haz the power, 2014-09-06 00:04:27]

CQ is trying da patch. Follow status at
 https://chromium-status.appspot.com/cq/mmoss@chromium.org/549643002/20001

[commit-bot: I haz the power, 2014-09-06 00:06:25]

Committed patchset #2 (id:20001) as 291840