Kits: Do not lose toolchains when using SDK-provided kits

The observed behavior is:

The first time you open Qt Creator from the Qt 5.6 package you get
the kit for the installed Qt version with a toolchain. The next time
you start the toolchain vanishes from the Kit.

Surprisingly nobody reported a bug about this:-/

Change-Id: I49545e11f02eadb73f583b134d9eadfc2adf3bec
Reviewed-by: Niels Weber <niels.weber@theqtcompany.com>

src/plugins/projectexplorer/kitmanager.cpp

@@ -171,6 +171,8 @@ void KitManager::restoreKits()
     Kit *toStore = 0;
     foreach (Kit *current, kitsToValidate) {
         toStore = current;
+        toStore->setup(); // Make sure all kitinformation are properly set up before merging them
+                          // with the information from the user settings file
 
         // Check whether we had this kit stored and prefer the stored one:
         for (int i = 0; i < kitsToCheck.count(); ++i) {
@@ -191,8 +193,6 @@ void KitManager::restoreKits()
                 break;
             }
         }
-        if (toStore == current)
-            toStore->setup();
         addKit(toStore);
         sdkKits << toStore;
     }