opensp: fixed to not generate and install documentation if xmlto is *not* installed

textproc/opensp/opensp.conf

@@ -2,7 +2,7 @@
 # This copyright note is auto-generated by ./scripts/Create-CopyPatch.
 #
 # Filename: package/.../opensp/opensp.conf
-# Copyright (C) 2010 The OpenSDE Project
+# Copyright (C) 2010 - 2012 The OpenSDE Project
 #
 # More information can be found in the files COPYING and README.
 #
@@ -12,6 +12,6 @@
 # GNU General Public License can be found in the file COPYING.
 # --- SDE-COPYRIGHT-NOTE-END ---
 
-if pkginstalled -f xmlto; then
+if ! pkginstalled -f xmlto; then
 	var_append extraconfopt ' ' "--disable-doc-build"
 fi