fix health check for self-signed certificates

[thatso]

Do not fail health check with self-signed certificates. Resolves #156 by adding the real URL to additionally ignore besides localhost.

[CLAassistant]

All committers have signed the CLA.

[mpfz0r]

Already fixed with #160 Thank you anyway :handshake:

[thatso]

Please check again: your mentioned fix is more than one year old and does not include my recent change. Running the current docker container gives me a state of unhealthy without my patch because it does not fall back to localhost but instead silently fails at the real URL.