component/open62541: add slapos python3 in PATH

component/open62541/buildout.cfg

@@ -5,6 +5,7 @@ parts = open62541
 extends =
   ../cmake/buildout.cfg
   ../patch/buildout.cfg
+  ../python3/buildout.cfg
   ../defaults.cfg
 
 [gcc]
@@ -30,4 +31,4 @@ configure-options =
 post-install =
   cp src/pubsub/*.h deps/open62541_queue.h @@LOCATION@@/include
 environement =
-  PATH=${patch:location}/bin:%(PATH)s
+  PATH=${python3:location}/bin:${patch:location}/bin:%(PATH)s