Add BeautifulSoup dependency for Horizon

This is a workaround for an undocumented dependency on the Python
BeautifulSoup package.  It fixes both Ubuntu and Fedora builds.

Fixes bug 1010968

Change-Id: If7f5d55c38d3b9ab677378c57839bc8f03898e2f
diff --git a/files/rpms/horizon b/files/rpms/horizon
index 3c5fbc1..5e36820 100644
--- a/files/rpms/horizon
+++ b/files/rpms/horizon
@@ -5,6 +5,7 @@
 mod_wsgi  # NOPRIME
 pylint
 python-anyjson
+python-BeautifulSoup
 python-boto
 python-coverage
 python-dateutil