[explorer/interfaces] Always sort output

Before, only the output of ifconfig was sorted.

cdist/conf/explorer/interfaces

@@ -21,10 +21,8 @@
 if command -v ip >/dev/null
 then
 	ip -o link show | sed -n 's/^[0-9]\+: \(.\+\): <.*/\1/p'
-
 elif command -v ifconfig >/dev/null
 then
-    ifconfig -a \
+	ifconfig -a | sed -n -E 's/^(.*)(:[[:space:]]*flags=|Link encap).*/\1/p'
-        | sed -n -E 's/^(.*)(:[[:space:]]*flags=|Link encap).*/\1/p' \
+fi \
  | sort -u
-fi