Remove CUSTOM_THEME_PATH setting

Horizon now uses the WEBROOT to populate the value of $webroot in
the CSS code. The CUSTOM_THEME_PATH pointing to the webroot theme
to explicitly set the same value is no longer necessary.

Closes-Bug: 1540801
Change-Id: Ic212796ee0905751ac3fd619bbbc902d25ea10d5
diff --git a/lib/horizon b/lib/horizon
index dca3111..abc1f6d 100644
--- a/lib/horizon
+++ b/lib/horizon
@@ -89,7 +89,6 @@
     cp $HORIZON_SETTINGS $local_settings
 
     _horizon_config_set $local_settings "" WEBROOT \"$HORIZON_APACHE_ROOT/\"
-    _horizon_config_set $local_settings "" CUSTOM_THEME_PATH \"themes/webroot\"
 
     _horizon_config_set $local_settings "" COMPRESS_OFFLINE True
     _horizon_config_set $local_settings "" OPENSTACK_KEYSTONE_DEFAULT_ROLE \"Member\"