Bug 1092880 - Preferences.jsm MIN_INT is off by one r=gavin

toolkit/modules/Preferences.jsm

@@ -16,7 +16,7 @@ Cu.import("resource://gre/modules/XPCOMUtils.jsm");
 // because the native preferences code treats integers as NSPR PRInt32s,
 // which are 32-bit signed integers on all platforms.
 const MAX_INT = 0x7FFFFFFF; // Math.pow(2, 31) - 1
-const MIN_INT = -MAX_INT;
+const MIN_INT = -0x80000000;
 
 this.Preferences =
   function Preferences(args) {