### Please describe the problem.
The webapp doesn't start.  There is no feedback as to what is wrong when starting the OS X app.  Makes for a very confusing behaviour.

When starting git-annex-webapp directly, it says:
git-annex: no git repository in /Users/lhunath/annex

### What steps will reproduce the problem?
Create a ~/annex that is not a git repo.

### What version of git-annex are you using? On what operating system?
git-annex version: 5.20140517-g0aed6d9
build flags: Assistant Webapp Webapp-secure Pairing Testsuite S3 WebDAV FsEvents XMPP DNS Feeds Quvi TDFA CryptoHash
key/value backends: SHA256E SHA1E SHA512E SHA224E SHA384E SKEIN256E SKEIN512E SHA256 SHA1 SHA512 SHA224 SHA384 SKEIN256 SKEIN512 WORM URL
remote types: git gcrypt S3 bup directory rsync web webdav tahoe glacier ddar hook external
local repository version: unknown
supported repository version: 5
upgrade supported from repository versions: 0 1 2 4

### Please provide any additional information below.

[[!format sh """
# If you can, paste a complete transcript of the problem occurring here.
# If the problem is with the git-annex assistant, paste in .git/annex/daemon.log
$ /Applications/git-annex.app/Contents/MacOS/git-annex-webapp
git-annex: no git repository in /Users/lhunath/annex
# End of transcript or log.
"""]]

> [[fixed|done]] --[[Joey]]
