[forms] fix form_needs_multipart implementation
problem
-------
The current implementation of form_needs_multipart goes down
recursively in all inlined forms to check if one of them needs
a multipart enctype.
If we have a relation definition as X part_of X, the previous
implementation potentially lead to an infinite recursion
#!/bin/sh -e
if [ "$1" = "purge" ] ; then
update-rc.d cubicweb remove >/dev/null
fi
#DEBHELPER#
exit 0