Add the manual to the build making it fully optional unless karaf is being released

git-svn-id: https://svn.apache.org/repos/asf/felix/trunk@824796 13f79535-47bb-0310-9956-ffa450edef68
diff --git a/karaf/manual/src/fallback/manual.html b/karaf/manual/src/fallback/manual.html
new file mode 100644
index 0000000..236f49a
--- /dev/null
+++ b/karaf/manual/src/fallback/manual.html
@@ -0,0 +1,3 @@
+<div class="wiki-content">
+    Unable to generate manual.
+</div>
\ No newline at end of file