Make global explorers available to initial manifest and fix hostname explorer

cdist/conf/explorer/hostname

@@ -20,6 +20,6 @@
 #
 #
 
-if command -v hostname; then
-   hostname
+if command -v hostname >/dev/null; then
+   hostname -f
 fi

cdist/core/manifest.py

@@ -106,6 +106,7 @@ class Manifest(object):
         env.update(self.env)
         env['__cdist_manifest'] = initial_manifest
         env['__manifest'] = self.local.manifest_path
+        env['__explorer'] = self.local.global_explorer_out_path
 
         return env