Fix cowHostList can't have hosts with same ConnectAddress

[dkropachev]

cowHostList uses HostInfo.Equal for host uniqueness, which relies on ConnectAddress.Equal, which does not allow to have different hosts with same ConnectAddress.

It breaks cases like accessing cluster via tcp or ssl proxy

Closes #1757

[OleksiienkoMykyta]

LGTM. Please, make it up to date, make the notation to the CHANGELOG.md, and change the commit message according to the CONTRIBUTING.md.
The commit message format should be:

<short description>

<reason why the change is needed>

Patch by <authors>; reviewed by <Reviewers> for CASSGO-#####

NIT: We shouldn't add code that we don't add/change, ConnectAddressAndPort() as an example in this case.

@jameshartig, @joao-r-reis, could we merge it after the update?

[dkropachev]

LGTM. Please, make it up to date, make the notation to the CHANGELOG.md, and change the commit message according to the CONTRIBUTING.md. The commit message format should be:

<short description>

<reason why the change is needed>

Patch by <authors>; reviewed by <Reviewers> for CASSGO-#####

NIT: We shouldn't add code that we don't add/change, ConnectAddressAndPort() as an example in this case.

@jameshartig, @joao-r-reis, could we merge it after the update?

Done

[joao-r-reis]

I don't want to increase the scope of the 2.0 release but I can add a 2.x fixversion to the JIRA if there is one