MINOR: http-rules: Handle internal errors during HTTP rules evaluation

MINOR: http-rules: Handle internal errors during HTTP rules evaluation

The HTTP_RULE_RES_ERROR code is now used by HTTP analyzers to handle internal
errors during HTTP rules evaluation. It is used instead of HTTP_RULE_RES_BADREQ,
used for invalid requests/responses. In addition, the SF_ERR_RESOURCE flag is
set on the stream when an allocation failure happens.

Note that the return value of http-response rules evaluation is now tested in
the same way than the result of http-request rules evaluation.