restore the original gevent detection

bzr revid: al@openerp.com-20130909231946-aglho23enxhfwm0i

openerp-gevent

@@ -7,7 +7,5 @@ psycogreen.gevent.patch_psycopg()
 
 import openerp
 
-openerp.evented = True
-
 if __name__ == "__main__":
     openerp.cli.main()

openerp/__init__.py

@@ -27,6 +27,8 @@ import sys
 
 # Is the server running with gevent.
 evented = False
+if sys.modules.get("gevent") is not None:
+    evented = True
 
 # Make sure the OpenERP server runs in UTC. This is especially necessary
 # under Windows as under Linux it seems the real import of time is