remove top-level directive page from basewiki

diff --git a/underlays/basewiki/directive.mdwn b/underlays/basewiki/directive.mdwn
deleted file mode 120000 (symlink)
index e8ce42c..0000000
--- a/underlays/basewiki/directive.mdwn
+++ /dev/null
@@ -1 +0,0 @@
-../../doc/ikiwiki/directive.mdwn
\ No newline at end of file