Only define screens after the config is loaded

This gives us the worst of both worlds: We still restart on RandR screen changes
and the information about screens isn't available during startup. However, it's
a step in the right direction, because all Lua code will now have to handle
kind-of-dynamic screen changes.

Signed-off-by: Uli Schlachter <psychon@znc.in>

awesome.c

@@ -643,9 +643,6 @@ main(int argc, char **argv)
     /* init atom cache */
     atoms_init(globalconf.connection);
 
-    /* init screens information */
-    screen_scan();
-
     /* do this only for real screen */
     ewmh_init();
     systray_init();
@@ -702,6 +699,9 @@ main(int argc, char **argv)
 
     xdgWipeHandle(&xdg);
 
+    /* init screens information */
+    screen_scan();
+
     /* scan existing windows */
     scan(tree_c);