Add pcre devel package for Horizon

pyScss python module uses pcre if available for performance
and it is better to be installed.
This commit adds it for files/{apts,rpms}/horizon.

Change-Id: If711fa222d3f395efd670334c8a84f35d195dc25
diff --git a/files/rpms/horizon b/files/rpms/horizon
index fe3a2f4..7add23a 100644
--- a/files/rpms/horizon
+++ b/files/rpms/horizon
@@ -19,3 +19,4 @@
 python-sqlalchemy
 python-webob
 pyxattr
+pcre-devel  # pyScss