Delete src because unused

diff --git a/src/django-haystack b/src/django-haystack
deleted file mode 160000 (submodule)
index 97475f2..0000000
--- a/src/django-haystack
+++ /dev/null
@@ -1 +0,0 @@
-Subproject commit 97475f2813a36e402296d5f2389fe10cd4cd1e0b