software/beremiz-runtime: fix installation of lxml and numpy eggs

software/beremiz-runtime/software.cfg

@@ -4,6 +4,8 @@ extends =
   ../../component/git/buildout.cfg
   ../../component/matiec/buildout.cfg
   ../../component/open62541/buildout.cfg
+  ../../component/numpy/buildout.cfg
+  ../../component/lxml-python/buildout.cfg
   ../../stack/monitor/buildout.cfg
   ../../stack/slapos.cfg
 
@@ -70,8 +72,8 @@ eggs = click
        Nevow
        msgpack
        autobahn
-       numpy
-       lxml
+       ${numpy:egg}
+       ${lxml-python:egg}
        cycler
        opcua
        ${beremiz:egg}
@@ -121,9 +123,7 @@ txaio = 18.8.1
 idna = 2.10
 
 click = 7.1.2
-lxml  = 4.5.0
 opcua = 0.98.13
 trollius = 2.2.1
 futures = 3.3.0
-numpy = 1.16.6
 cycler = 0.10.0