Python: Switch pyls on interpreter change

Change-Id: I458b635986a55003a1e7254e27e2df9667704273
Reviewed-by: Christian Stenger <christian.stenger@qt.io>

src/plugins/python/python.qbs

@@ -33,6 +33,8 @@ QtcPlugin {
             "pythonscanner.cpp",
             "pythonsettings.cpp",
             "pythonsettings.h",
+            "pythonutils.cpp",
+            "pythonutils.h",
         ]
     }
 }