fixing a path to find charset by $MYSQL client. I believe the fix is done what should be
by default. 


mysql-test/t/mysqlbinlog.test:
  --character-sets-dir=../sql/share/charsets  is added otherwise client/.libs/lt-mysql
  searches in /usr/local/mysql ... A bug?
mysql-test/t/rpl_temporary.test:
  --character-sets-dir=../sql/share/charsets/