[yelp-tools] yelp-build: Fixed 'yelp-build epub --help'

[Shaun McCance <shaunm src gnome org>]

commit d5c8fc3622e0f182ff9b38ff13b81a54fa9a2eaa
Author: Shaun McCance <shaunm gnome org>
Date:   Thu Sep 6 13:18:31 2012 -0400

    yelp-build: Fixed 'yelp-build epub --help'

 tools/yelp-build.in |    4 ++++
 1 files changed, 4 insertions(+), 0 deletions(-)
---
diff --git a/tools/yelp-build.in b/tools/yelp-build.in
index e0f1ed2..1d70145 100755
--- a/tools/yelp-build.in
+++ b/tools/yelp-build.in
@@ -556,6 +556,10 @@ yelp_epub () {
                 ;;
         esac
     done
+    if [ "$#" = "0" -o "x$1" = "x--help" ]; then
+        yelp_usage_epub
+        exit 1
+    fi
     if [ "x$epub_cache_file" != "x" ]; then
         epub_cache_file=`(cd $(dirname "$epub_cache_file") && pwd)`/`basename "$epub_cache_file"`
     else