title: ProxyRemote works with HTTP URL but not with HTTPS
body: <p>ProxyRemote Directive doesn't work with HTTPS:</p>
  
  <pre><code>    &lt;VirtualHost *:443&gt;
      ServerName foo.foo
  
      SSLProxyEngine on
      SSLProxyVerify none
      #SSLProxyVerifyDepth 10
      SSLProxyCheckPeerCN off
      # SAAS: disable hostname check
      SSLProxyCheckPeerName off
      SSLProxyCheckPeerExpire off
  
      SSLProxyCACertificatePath /etc/ssl/certs/
  
  
      ProxyRemote * https://10.27.73.178:443/
      ProxyPass /api/ https://foo.gw.dev/api/
      ProxyPassReverse /api/ https://foo.gw.dev/api/
  
      SSLEngine on
      SSLCertificateFile /storage/user/conf/ssl/web_cert.pem
      SSLCertificateKeyFile /storage/user/conf/ssl/web_key.pem
      SSLCertificateChainFile /storage/user/conf/ssl/web_chain.pem
  
  
      SSLCACertificatePath /storage/user/conf/ssl/
      SSLVerifyClient none
      &lt;/VirtualHost&gt;
  </code></pre>
  
  <p>It works if I specify http URL, like </p>
  
  <pre><code>    ProxyRemote * http://10.27.73.178:3128/
  </code></pre>
  
  <p>I think it is a certificate checking issue, where exactly should I specify the proxy CA certificate?</p>
  
  <p>I get the following error logs:</p>
  
  <pre><code>[Wed Nov 27 14:35:40.961981 2019] [proxy_http:trace1] [pid 32633:tid 140286441285376] mod_proxy_http.c(1931): [client 127.0.0.1:54302] HTTP: serving URL https://foo.gw.dev/api/
  [Wed Nov 27 14:35:40.961989 2019] [proxy:debug] [pid 32633:tid 140286441285376] proxy_util.c(2302): AH00942: HTTPS: has acquired connection for (foo.gw.dev)
  [Wed Nov 27 14:35:40.961993 2019] [proxy:debug] [pid 32633:tid 140286441285376] proxy_util.c(2355): [client 127.0.0.1:54302] AH00944: connecting https://foo.gw.dev/api/ to foo.gw.dev:443
  [Wed Nov 27 14:35:40.962067 2019] [proxy:debug] [pid 32633:tid 140286441285376] proxy_util.c(2564): [client 127.0.0.1:54302] AH00947: connected /api to 10.27.73.178:443
  [Wed Nov 27 14:35:40.962086 2019] [proxy:trace2] [pid 32633:tid 140286441285376] proxy_util.c(2999): HTTPS: fam 2 socket created to connect to foo.gw.dev
  [Wed Nov 27 14:35:41.172521 2019] [proxy:debug] [pid 32633:tid 140286441285376] proxy_util.c(3033): AH02824: HTTPS: connection established with 10.27.73.178:443 (foo.gw.dev)
  [Wed Nov 27 14:35:41.172570 2019] [proxy:debug] [pid 32633:tid 140286441285376] proxy_util.c(2660): AH00948: CONNECT: sending the CONNECT request for foo.gw.dev:443 to the remote proxy 10.27.73.178:443 (10.27.73.178)
  [Wed Nov 27 14:35:41.383758 2019] [proxy:error] [pid 32633:tid 140286441285376] (104)Connection reset by peer: AH00958: HTTPS: attempt to connect to foo.gw.dev:443 via http CONNECT through 10.27.73.178:443 (foo.gw.dev) failed
  [Wed Nov 27 14:35:41.383798 2019] [proxy_http:error] [pid 32633:tid 140286441285376] [client 127.0.0.1:54302] AH01114: HTTP: failed to make connection to backend: 10.27.73.178
  [Wed Nov 27 14:35:41.383802 2019] [proxy:debug] [pid 32633:tid 140286441285376] proxy_util.c(2317): AH00943: HTTPS: has released connection for (foo.gw.dev)
  </code></pre>