Minor issues with https website?

See: Domain Name: h-node.org
URL Tested: https://h-node.org
Number of items downloaded on page: 63 All 63 items called securely!

Valid Certificate found.
Certificate valid through: Aug 27 23:59:59 2015 GMT

Certificate Issuer: GANDI SAS
SSL Protocols Supported: TLSv1
All 63 items called securely!
Secure calls made to other websites:
savannah.nongnu.org SSL verification issue (Possibly mis-matched URL or bad intermediate cert.). Details:
ERROR: cannot verify -savannah.nongnu.org’s certificate, issued by ‘/C=FR/ST=Paris/L=Paris/O=Gandi/CN=Gandi Standard SSL CA 2’:

-static.fsf.org is valid and secure.

-www.gnu.org is valid and secure.

-upload.wikimedia.org is valid and secure.

Comodo does not see anything out of the ordinairy: https://app.webinspector.com/public/reports/31447515

Well, we have ignature Algorithm sha1WithRSAEncryption (SHA-1 is being phased out), which is confirmed here:
http://toolbar.netcraft.com/site_report/?url=https%3A%2F%2Fh-node.org%2F

Netcraft risk status 1 red out of 10. Missing Name servers, only 1 given: http://www.dnsinspect.com/h-node.org/1427148587

Not returned were these security headers:
cache-control
no-cache

x-content-type-options
Header not returned

x-xss-protection
Header not returned

x-frame-options
Header not returned

content-security-policy
Header not returned

polonus