Fix '$bin' path duplication in setup scripts

I have my bash environment setup to echo absolute pathnames when a relative one is specified in 'cd'. This caused problems with all the Hadoop bash scripts because the script accidentally sets the $bin variable twice in this setup. (e.g. would set $bin="/path/bin/hbase\n/path/bin/hbase")

This jira is for HBase scripts. I filed a separate jira for HDFS scripts, which share the same pattern.