url: Update current connection SSL verify params in setopt

Now VERIFYHOST, VERIFYPEER and VERIFYSTATUS options change during active
connection updates the current connection's (i.e.'connectdata'
structure) appropriate ssl_config (and ssl_proxy_config) structures
variables, making these options effective for ongoing connection.

This functionality was available before and was broken by the
following change:
"proxy: Support HTTPS proxy and SOCKS+HTTP(s)"
CommitId: cb4e2be7.

Bug: https://github.com/curl/curl/issues/1941

Closes https://github.com/curl/curl/pull/1951