daemon: use "require" to make eggs available for import

Since version 5.0, python modules (e.g. core, corens3, and netns)
are installed as .egg bundles, and are not available for importing
by default, unless explicitly we use "pkg-resources.require()".

Signed-off-by: Gabriel Somlo <glsomlo@cert.org>

daemon/sbin/core-daemon

@@ -25,6 +25,9 @@ import sys
 import threading
 import time
 
+from pkg_resources import require
+require("core_python", "corens3_python", "core_python_netns")
+
 from core import constants
 from core import corehandlers
 from core import coreserver