Bug 694570 - (2/4) - Annotate deliberate leak in SaveToEnv. r=karlt

Required now because the setenv calls in nsNativeAppSupportUnix::Start somehow
prevent the leak in putenv from occurring. These setenv calls will be removed
in the next patch.

toolkit/xre/nsAppRunner.cpp

@@ -287,6 +287,7 @@ SaveToEnv(const char *putenv)
   if (expr)
     PR_SetEnv(expr);
   // We intentionally leak |expr| here since it is required by PR_SetEnv.
+  MOZ_LSAN_INTENTIONALLY_LEAK_OBJECT(expr);
 }
 
 // Tests that an environment variable exists and has a value