Bug 1256307: Only print via the parent in Nightly. r=jimm

modules/libpref/init/all.js

@@ -1027,7 +1027,7 @@ pref("print.print_edge_right", 0);
 pref("print.print_edge_bottom", 0);
 
 // Print via the parent process. This is only used when e10s is enabled.
-#if defined(XP_WIN)
+#if defined(XP_WIN) && defined(NIGHTLY_BUILD)
 pref("print.print_via_parent", true);
 #else
 pref("print.print_via_parent", false);