Check EXCH protocol if EXPR protocol has no EwsUrl
Check EXCH protocol if EXPR protocol has no EwsUrl

Some providers appear to specify the EwsUrl in the EXCH protocol rather
than the EXPR protocol.

Though this isn't technically correct if we didn't find one in the EXPR
protocol, we may as well try using the one in the EXCH protocol.

cronofy/autodiscover