schannel: allow verifyhost independently of verifypeer

Prior to this change if the user disabled the verify peer check then no
host check was done. Empirical testing shows
SCH_CRED_MANUAL_CRED_VALIDATION, which we use when peer verification is
disabled, also disables hostname verification.

In Windows < 8 our manual host verification check (ie the check used
when CA info is specified, or peer verification is disabled, or WinCE is
the OS) for schannel continues to only check the first subject alternate
name, and not all the names, since there is no easy way supported by the
API. It looks possible to do just more work, and should be addressed
separately.

Assisted-by: Daniel Stenberg
Reported-by: Martin Galvan

Fixes #3284
Closes #3285
Closes #xxxx