What steps will reproduce the problem?

Download the sourcecode, build using 'cabal build', then install using 'cabal install --bindir ~/bin'. 

What is the expected output? What do you see instead?

The .desktop file contains `~/bin/git-annex webapp` as command which is of course a invalid command as ~ is not expanded when running the desktop file. 

What version of git-annex are you using? On what operating system?
Latest Head from git, Ubuntu 12.04

Please provide any additional information below.
I'm not sure whether this is a bug or not. I just ran into problems because I did not expect the cabal build process to create my desktop file but instead thought that git-annex will create it by it-self taking its own path. Perhaps it would make sense to produce an error if the bindir is invalid. An automatic expansion of '~' in the build script would be even better.

> [[done]], I think it was a typo. --[[Joey]]
