Avoid infinite recursion on verbose mudflap

From: Alexandre Oliva <aoliva@redhat.com>

for  libmudflap/ChangeLog

	* mf-hooks1.c (free): Return on NULL before any logging.
---

 libmudflap/mf-hooks1.c |    4 ++--
 1 files changed, 2 insertions(+), 2 deletions(-)


diff --git a/libmudflap/mf-hooks1.c b/libmudflap/mf-hooks1.c
index 3dd332e..7a27321 100644
--- a/libmudflap/mf-hooks1.c
+++ b/libmudflap/mf-hooks1.c
@@ -238,11 +238,11 @@ WRAPPER(void, free, void *buf)
   static int freeq_initialized = 0;
   DECLARE(void, free, void *);
 
-  BEGIN_PROTECT (free, buf);
-
   if (UNLIKELY(buf == NULL))
     return;
 
+  BEGIN_PROTECT (free, buf);
+
 #if PIC
   /* Check whether the given buffer might have come from a
      __mf_0fn_malloc/calloc call that for whatever reason was not