BUG/MINOR: Fix prometheus '# TYPE' and '# HELP' headers

Prometheus protocol defines HELP and TYPE as a token after the '#' and
the space after the '#' is necessary.
This is expected in the prometheus python client for example
(https://github.com/prometheus/client_python/blob/a8f5c80f651ea570577c364203e0edbef67db727/prometheus_client/parser.py#L194)
and the missing space is breaking the parsing of metrics' type.

This patch must be backported to 2.0.

(cherry picked from commit 51c3aa4628cf597eb133f6ae8bb36e09139a73dc)
Signed-off-by: Christopher Faulet <cfaulet@haproxy.com>
1 file changed