fix boundary condition on reporting prior-to-next-malloc msg
fix boundary condition on reporting prior-to-next-malloc msg

SVN-Revision: 1986

code4bones/drmemory,LohithBlaze/drmemory,sigma-random/drmemory,sigma-random/drmemory,sigma-random/drmemory,sigma-random/drmemory,sigma-random/drmemory,LohithBlaze/drmemory,code4bones/drmemory,code4bones/drmemory,LohithBlaze/drmemory,code4bones/drmemory,LohithBlaze/drmemory,code4bones/drmemory,LohithBlaze/drmemory