As reported here
this is an annoying problem because when (i.e.) you close an hotfix you got 2 merge message and one tag message to fill in.
The --no-edit option should be added to avoid this.
Upgraded to ubuntu quantal which includes git 1.7.10 and can confirm this issue.
The --no-edit can only be used with git 1.7.8 or higher.
Why not just do the alternative method by adding this in your environment.
On Ubuntu this would go into the file: ~/.bash_export