Added test cases

mysql-test/r/mysql_tzinfo_to_sql_symlink.result:
  Updated results
mysql-test/std_data/zoneinfo/garbage:
  test file
mysql-test/std_data/zoneinfo/ignored.tab:
  test file
mysql-test/t/mysql_tzinfo_to_sql_symlink.test:
  Added test cases for all options
sql/tztime.cc:
  Better error messages.
  Fixed wrong place for 'continue'