pkg-config: fix target package

As reported by Sven Neumann on the list.
diff --git a/package/Config.in b/package/Config.in
index 004894b..4189af0 100644
--- a/package/Config.in
+++ b/package/Config.in
@@ -43,7 +43,7 @@
 source "package/m4/Config.in"
 source "package/mpatrol/Config.in"
 source "package/oprofile/Config.in"
-source "package/pkgconfig/Config.in"
+source "package/pkg-config/Config.in"
 source "package/readline/Config.in"
 source "package/valgrind/Config.in"
 source "package/pcre/Config.in"