ProjectExplorer: Don't register targets that are restored to empty state

Don't accept targets that get restored to an empty state. This un-confuses
the Projects page:-) Note that DeployConfigurations are not tested:
I see no use-case where a target with only a deploy configuration makes
any sense.

This can be triggered, e.g. by opening an existing cmake project after
making sure there are no more kits with cmake tool set up.

Change-Id: Iaf14f70e4e0d4206a88a08b47b0eccc666653f76
Reviewed-by: Eike Ziller <eike.ziller@qt.io>

src/plugins/projectexplorer/project.cpp

@@ -701,6 +701,11 @@ void Project::createTargetFromMap(const QVariantMap &map, int index)
     Target *t = restoreTarget(targetMap);
     if (!t)
         return;
+    if (t->runConfigurations().isEmpty() && t->buildConfigurations().isEmpty()) {
+        delete t;
+        return;
+    }
+
 
     addTarget(t);
 }