Host header default and proxies

[ctrimble]

Defaulting the Host header to the local interfaces host name may not be the best default. When connecting to Etcd behind a proxy, the host header needs to match the host being contacted, otherwise the proxy will fail.

A better default would be to extract the host from the url being connected to. This would allow proxies to work as expected.

[jurmous]

Thanks for reporting this issue! It is indeed more sensible to use the host name of the URI being connected to.

[ctrimble]

@jurmous, thanks for changing this. You may want to update the README.md as well, since it specifies the default behavior.

[jurmous]

Thanks for pointing me out! I will update it when this fix will be released in the next version. This way it will not confuse people visiting the github page and working with the current version.

[jurmous]

Released in 2.7.0 and I updated the README. Thanks!