component/opencv: explicitly use slapos python

This software autodetects python2 and python3, so provide both

component/opencv/buildout.cfg

@@ -4,6 +4,9 @@ extends =
   ../java-jdk/buildout.cfg
   ../cmake/buildout.cfg
   ../libjpeg/buildout.cfg
+  ../python-2.7/buildout.cfg
+  ../python3/buildout.cfg
+  ../defaults.cfg
 parts =
   opencv
 
@@ -57,7 +60,7 @@ post-install =
   cp build/lib/libopencv_java430.so @@LOCATION@@/lib
   cp build/bin/opencv-430.jar @@LOCATION@@/bin
 environment =
-  PATH=${cmake:location}/bin:${pkgconfig:location}/bin:%(PATH)s
+  PATH=${python3:location}/bin/:${python2.7:location}/bin/:${cmake:location}/bin:${pkgconfig:location}/bin:%(PATH)s
   PKG_CONFIG_PATH=${zlib:location}/lib/pkgconfig:${libpng:location}/lib/pkgconfig:${libjpeg-turbo2:location}/lib/pkgconfig
   JAVA_HOME=${java-jdk:location}
   JRE_HOME=${java-re:location}