Put in a sanity check for permissions='string' in context setup; permissions

should not be a string, use permission='string' for that. The behavior
for iterating over all elements of a string is of course to create lots of
single-letter permissions.

This fixes Collector issue 22, from runyaga

lib/python/App/ProductContext.py

@@ -175,6 +175,9 @@ class ProductContext:
         OM=OFS.ObjectManager.ObjectManager
 
         if permissions:
+            if type(permissions) is type(''): # You goofed it!
+                raise TypeError, ('Product context permissions should be a '
+                    'list of permissions not a string', permissions)
             for p in permissions:
                 if type(p) is tt:
                     p, default= p