http-after-response rules evaluation must be stopped after a "allow". It
means the frontend ruleset must not be evaluated if a "allow" was performed
in the backend ruleset. Internally, the evaluation must be stopped if on
HTTP_RULE_RES_STOP return value. Only the "allow" action is concerned by
this change.
Thanks to this patch, http-response and http-after-response behave in the
same way.
This patch should be backported as far as 2.2.
A reg test has been added to ensure the evaluation of http-after-responses rules
is functionnal for all kind of responses (server, applet and internal
responses).
