EXT_CLASSPATH strips out directories

in storm.py we are splitting up STORM_EXT_CLASSPATH and STORM_EXT_CLASSPATH_DAEMON then processing each entry with get_wildcard_dir. the problem is that if we pass in a directory (say for configuration like $STORM_HOME/conf) it will translate this to $STORM_HOME/conf/* which is not what a classpath does. We should just leave true classpaths alone.