This is a followup patch for the bug enabling the test
i_binlog.binlog_mysqlbinlog_file_write.test
this was disabled in mysql trunk and mysql 5.5 as in the release
build mysqlbinlog was not debug compiled whereas the mysqld was.
Since have_debug.inc script checks only for mysqld to be debug
compiled, the test was not being skipped on release builds.

We resolve this problem by creating a new inc file 
mysqlbinlog_have_debug.inc which checks exclusively for mysqlbinlog
to be debug compiled. if not it skips the test.