Revert "elua: more reliable eoid->lua number conversion"

This reverts commit 8bb13b626f.

Seems like this method is not so reliable after all :) Results
in precision loss for Eo IDs, so revert to the old hacky way.

src/bindings/luajit/eo.lua

@@ -110,8 +110,11 @@ ffi.cdef [[
     extern const Eo_Event_Description _EO_BASE_EVENT_DEL;
 ]]
 
+local addr_d = ffi.typeof("union { double d; const Eo *p; }")
 local eo_obj_addr_get = function(x)
-    return tonumber(ffi.cast("intptr_t", x))
+    local v = addr_d()
+    v.p = x
+    return tonumber(v.d)
 end
 
 local cutil = require("cutil")