add OS and versions

[knoguchi]

As of now the supported OS is RedHat Enterprise 6 "el6" only that is defined in config.mk. Add more OS and versions that CDH supports.

Possible distro suffixes

• el5: Redhat Enterprise Linux 5 and clones (CentOS, Scientific Linux, etc)
• el6: Redhat Enterprise Linux 6 and clones (CentOS, Scientific Linux, etc)
• el7: Redhat Enterprise Linux 7 and clones (CentOS, Scientific Linux, etc)
• sles11: SuSE Linux Enterprise Server 11.x
• lucid: Ubuntu Linux 10.04 LTS (No CDH 5.x parcel provided)
• precise: Ubuntu Linux 12.04 LTS
• trusty: Ubuntu Linux 14.04 LTS (Newly supported in CM 5.2. No CDH 4.x parcel provided)
• squeeze: Debian 6.x (No CDH 5.x parcel provided))
• wheezy: Debian 7.x (Newly supported in CM 5.0. No CDH 4.x parcel provided)