install constraint so we've fallback opportunity if gecode is not installed

ChangeLog

@@ -3,7 +3,10 @@
 
 --
     * enhance bad rql query detection with ordered distinct (can't use distinct
-      if an attribute is selected and we order on another attribute)
+      if an attribute is selected and we sort on another attribute)
+
+    * add constraint package to dependencies  so we've fallback opportunity if
+      gecode is not installed
 
 2010-08-02  --  0.26.5
     * fix solutions computation crash with some query using sub-queries (closes #37423)

__pkginfo__.py

@@ -83,6 +83,7 @@
     'logilab-common >= 0.47.0',
     'logilab-database',
     'yapps2 >= 2.1.1',
+    'constraint', # fallback if the gecode compiled module is missing
     ]
 
 # links to download yapps2 package that is not (yet) registered in pypi