i3: Abort build if test suite is failing.

The exit code of the i3 test runner is always 0, regardless of whether
tests were failing or not, so let's quickly grep for a "not ok" in the
test logfile and if it occurs, the whole build is failing now.

Signed-off-by: aszlig <aszlig@redmoonstudios.org>

pkgs/applications/window-managers/i3/default.nix

@@ -28,6 +28,7 @@ stdenv.mkDerivation rec {
   checkPhase = ''
     ln -sf "${xdummy}/bin/xdummy" testcases/Xdummy
     (cd testcases && perl complete-run.pl)
+    ! grep -q '^not ok' testcases/latest/complete-run.log
   '';
 
   configurePhase = "makeFlags=PREFIX=$out";