i#769 improvement: create default pcache dir if not present
i#769 improvement: create default pcache dir if not present

SVN-Revision: 823

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