Fix broken .config/git-annex/program installed by standalone tarball.

It was doubly broken; both missing a slash, and containing
"runshell git-annex", while some parts of the code expected it to be a
simple path to a program. This appears to include the transfer queue
runner, and the code that starts a new assistant process when switching to
another repository in the webapp.

Assistant/Install.hs

@@ -39,7 +39,7 @@ ensureInstalled = go =<< standaloneAppBase
   where
 	go Nothing = noop
 	go (Just base) = do
-		let program = base ++ "runshell git-annex"
+		let program = base <$> "git-annex"
 		programfile <- programFile
 		createDirectoryIfMissing True (parentDir programfile)
 		writeFile programfile program