BUG/MEDIUM: map/acl: fix unwanted flags inheritance.

BUG/MEDIUM: map/acl: fix unwanted flags inheritance.

The bug: Maps/ACLs using the same file/id can mistakenly inherit
their flags from the last declared one.

i.e.

    $ cat haproxy.conf
    listen mylistener
	mode http
	bind 0.0.0.0:8080

	acl myacl1 url -i -f mine.acl
	acl myacl2 url -f mine.acl
	acl myacl3 url -i -f mine.acl
	redirect location / if myacl2
    $ cat mine.acl
    foobar

Shows an unexpected redirect for request 'GET /FOObAR HTTP/1.0\n\n'.

This fix should be backported on mainline branches v1.6 and v1.7.