ProjectConfiguration: Add project() member

Change-Id: I0a7170c1721a9e5bcf18af1bab8158af71c64454
Reviewed-by: Tim Jenssen <tim.jenssen@qt.io>
Reviewed-by: Tobias Hunger <tobias.hunger@qt.io>

src/plugins/projectexplorer/buildsteplist.cpp

@@ -198,3 +198,8 @@ Target *BuildStepList::target() const
         return dc->target();
     return 0;
 }
+
+Project *BuildStepList::project() const
+{
+    return target()->project();
+}