doc: mention Go requires OpenBSD 5.9 or above in go1.8.html
doc: mention Go requires OpenBSD 5.9 or above in go1.8.html

Change-Id: Ia19e4d2f319002b5b26e50258436f5c4bd281cc7
Reviewed-on: https://go-review.googlesource.com/34113
Reviewed-by: Brad Fitzpatrick <ae9783c0b0efc69cd85ab025ddd17aa44cdc4aa5@golang.org>

cloudflare/go,ImJasonH/go,cloudflare/go,vsekhar/elastic-go,golang/go,Cofyc/go,josharian/go,linux-on-ibm-z/go,codestation/go,polyverse-security/go,Cofyc/go,polyverse-security/go,suncycheng/go,CAFxX/go,vsekhar/elastic-go,akutz/go,nawawi/go,linux-on-ibm-z/go,codestation/go,ImJasonH/go,cloudflare/go,CAFxX/go,derekmarcotte/go,codestation/go,akutz/go,cloudflare/go,codestation/go,suncycheng/go,derekmarcotte/go,Cofyc/go,akutz/go,vsekhar/elastic-go,golang/go,CAFxX/go,golang/go,nawawi/go,josharian/go,CAFxX/go,akutz/go,derekmarcotte/go,CAFxX/go,derekmarcotte/go,Cofyc/go,derekmarcotte/go,vsekhar/elastic-go,Cofyc/go,ImJasonH/go,cloudflare/go,suncycheng/go,josharian/go,golang/go,golang/go,derekmarcotte/go,christopher-henderson/Go,derekmarcotte/go,codestation/go,linux-on-ibm-z/go,nawawi/go,josharian/go,suncycheng/go,akutz/go,linux-on-ibm-z/go,cloudflare/go,Cofyc/go,linux-on-ibm-z/go,ImJasonH/go,linux-on-ibm-z/go,akutz/go,nawawi/go,nawawi/go,vsekhar/elastic-go,suncycheng/go,josharian/go,polyverse-security/go,nawawi/go,linux-on-ibm-z/go,CAFxX/go,derekmarcotte/go,ImJasonH/go,CAFxX/go,codestation/go,ImJasonH/go,codestation/go,polyverse-security/go,ImJasonH/go,vsekhar/elastic-go,suncycheng/go,linux-on-ibm-z/go,suncycheng/go,polyverse-security/go,josharian/go,josharian/go,nawawi/go,Cofyc/go,CAFxX/go,vsekhar/elastic-go,akutz/go,golang/go,codestation/go,Cofyc/go,ImJasonH/go,polyverse-security/go,nawawi/go,cloudflare/go,golang/go,polyverse-security/go,akutz/go,suncycheng/go,cloudflare/go,josharian/go,polyverse-security/go,golang/go,vsekhar/elastic-go