MINOR: config: Add failifnotcap() to emit an alert on proxy capabilities

This function must be used to emit an alert if a proxy does not have at
least one of the requested capabilities. An additional message may be
appended to the alert.

(cherry picked from commit d4a83dd6b30a68605f13a447b398a15ab38f28d4)
Signed-off-by: Christopher Faulet <cfaulet@haproxy.com>
1 file changed