[predicates] fix predicates that erroneously evaluate the entity passed as a parameter as a boolean, instead of testing its existence in the keyword arguments -using the kwargs.get('entity') idiom instead of 'entity' in kwargs or similar- ; closes #2424288

#! /bin/sh -e
#

if [ "$1" = configure ]; then
  if which install-docs >/dev/null 2>&1; then
    install-docs -i /usr/share/doc-base/cubicweb-doc
  fi
fi


#DEBHELPER#

exit 0