Expands bp_rules t flag from tags rather than use

Tags are now recursed, which is not the case for templates in the `use`
parameter.

This patch expands the `t` flag in business rules expand expressions against
`tags` rather than direct templates in `use`.
Merge pull request #1339 from geektophe/bp_rule_tag_expression_expansion_fix

Expands bp_rules t flag from tags rather than use