Fixed bug#12403662 (formerly known as bug#60987): LOAD DATA LOCAL INFILE

can't parse relative paths "higher" than 3 levels up

When trying to LOAD DATA LOCAL INFILE using a relative path with 3 or
more levels up in the directory hierarchy, mysqld wrongly parses 
the path and as a consequence, can't find the file.

This bug was introduced by patch for bug#58205.
The reason for bug is that implementaiton of function cleanup_dirname()
doesn't take into account the begin of buffer being processed during
handling of path to file.


mysys/mf_pack.c:
  function cleanup_dirname() was modified: fixed wrong comparison
  condition when handling substring "../" at the begining of the buffer.

mysys/mf_pack.c

@@ -193,7 +193,7 @@ size_t cleanup_dirname(register char *to, const char *from)
 	  while (pos >= start && *pos != FN_LIBCHAR)	/* remove prev dir */
 	    pos--;
           if (pos[1] == FN_HOMELIB ||
-              (pos > start && memcmp(pos, parent, length) == 0))
+              (pos >= start && memcmp(pos, parent, length) == 0))
 	  {					/* Don't remove ~user/ */
 	    pos=strmov(end_parentdir+1,parent);
 	    *pos=FN_LIBCHAR;