Fixed option for symlinks


Docs/manual.texi:
  Updated symlink handling.
sql-bench/Comments/postgres.benchmark:
  Updated benchmark text
sql-bench/Makefile.am:
  Added graph-compare-results
sql-bench/compare-results.sh:
  Don't reset the cmp option.
sql-bench/crash-me.sh:
  Updated transaction testing.
sql-bench/limits/mysql-3.23.cfg:
  Updated benchmark run
sql-bench/limits/mysql.cfg:
  Updated benchmark run
sql-bench/limits/pg.cfg:
  Updated benchmark run
sql-bench/server-cfg.sh:
  Don't do vacuum too often.
sql-bench/test-insert.sh:
  Don't do vacuum too often.
sql/mysqld.cc:
  Changed skip-symlinks to skip-symlink