doc: use HTTPS for man.openbsd.org link in go1.7.html
doc: use HTTPS for man.openbsd.org link in go1.7.html

Change-Id: I88855dfa3166e90386c90bf6220be0596dab3c0d
Reviewed-on: https://go-review.googlesource.com/118175
Reviewed-by: Brad Fitzpatrick <ae9783c0b0efc69cd85ab025ddd17aa44cdc4aa5@golang.org>

josharian/go,CAFxX/go,cloudflare/go,CAFxX/go,josharian/go,golang/go,CAFxX/go,cloudflare/go,josharian/go,golang/go,akutz/go,josharian/go,CAFxX/go,josharian/go,josharian/go,nawawi/go,nawawi/go,golang/go,nawawi/go,josharian/go,nawawi/go,akutz/go,nawawi/go,josharian/go,akutz/go,akutz/go,cloudflare/go,CAFxX/go,akutz/go,CAFxX/go,golang/go,cloudflare/go,golang/go,akutz/go,cloudflare/go,golang/go,nawawi/go,CAFxX/go,cloudflare/go,akutz/go,CAFxX/go,nawawi/go,akutz/go,nawawi/go,golang/go,cloudflare/go,golang/go,cloudflare/go