Provide explicit failure reason when connection can't be established

Reviewed By: jknoxville

Differential Revision: D22999785

fbshipit-source-id: 301ec8230a89ee9dbc82d006fa6520d8bac80b3e

xplat/Flipper/FlipperConnectionManagerImpl.cpp

@@ -198,6 +198,7 @@ bool FlipperConnectionManagerImpl::doCertificateExchange() {
           .get();
 
   if (newClient.get() == nullptr) {
+    connectingInsecurely->fail("Failed to connect");
     return false;
   }
 
@@ -257,6 +258,7 @@ bool FlipperConnectionManagerImpl::connectSecurely() {
           })
           .get();
   if (newClient.get() == nullptr) {
+    connectingSecurely->fail("Failed to connect");
     return false;
   }