This patch fixes the bug which caused the funcs_1.storedproc

test case to give valgrind warnings.

The problem was that when comparing two MDL key buffers using
memcmp(), 1 was added to the buffer length. However, this was
no longer needed since the buffer length already included the
'\0' terminator.

sql/mdl.h

@@ -252,7 +252,7 @@ public:
       character set is utf-8, we can safely assume that no
       character starts with a zero byte.
     */
-    return memcmp(m_ptr, rhs->m_ptr, min(m_length, rhs->m_length)+1);
+    return memcmp(m_ptr, rhs->m_ptr, min(m_length, rhs->m_length));
   }
 
   MDL_key(const MDL_key *rhs)